USA v. Alex Ruiz - Criminal Conviction Affirmed

FOR PUBLICATION UNITED STATES COURT OF A PPEALS FOR THE NI NTH CIRCUIT UNITED STATES OF AMERICA, Plaintiff - Appellee, v. ALEX RUIZ, Defendant - Appellant. No. 24-386 D.C. No. 3:23- cr -01331- GPC-1 AMENDED OPINION Appeal from the United States District Court for the Southern District of California Gonzalo P. Curiel, District Judge, Presiding Argued and Submitted October 21, 2025 Pasadena, California Filed January 7, 2026 Amended February 20, 2026 Before: Ryan D. Nelson and Lawrence VanDyke, Circuit Judges, and Douglas Russell Cole, District Judge. * Opinion by Judge Cole * The Honorab le Douglas Rus sell Cole, United State s District Judge for the Southern District o f Ohio, sitting by design ation.

2 USA V. R UIZ SUMMARY ** Criminal Law The panel affirmed Alex Ruiz’s convictio n for transporting illegal aliens in violation of 8 U.S.C. § 1324, in a case in which Ruiz a rgued that the district court abused its discretion in admitting into evidence a previous conviction he received for the same crime. The panel held that the district court did not abuse its discretion in admitt ing the prior conviction under Fed. R. Evid. 404(b), as that conviction satisfied each prong of the test for admission: it tended to prove the materia l point of knowledge; two years is not too remote in time; the stipulation and redacted documents provided sufficient evidence of the prior bad act; and, to the extent similarity is needed, the prior crime was sufficiently similar to the offense charged. Noting that the record shows that the district court implicitly considered the balancing test required by Fed. R. Evid. 403, the panel he ld that the district court did not a buse its discretion in performing this balancing and that any resulting prejudice did not subst antially outweigh the probative value of the prior conviction. Because Ruiz did not raise in the dist rict court his arguments that admitting the prior conviction violated both due process and the Sixth Amendment, the panel reviewed ** This summar y co nstitutes n o p art of the opinion of the court. It has been prepared b y court staff for the convenience of the r eader.

USA V. R UIZ 3 the constitutional challenge for plain error, which Ruiz did not show. COUNSEL Peter Horn (argued), Eric Olah, and Shivanjali A. Sewak, Assistant United State s Attorneys; Daniel E. Zipp, Assistant United States Attorney, Chief, Appellate Section, Criminal Division; Adam Gordon, United States Attorney; Office of the United States Attorney, United States Department of Justice, San Diego, California; for Plaintiff-Appellee. Benjamin P. Lechman (argued), Law Of fices of Benjamin P. Lechman Esq., Los Angeles, C alifornia, for Defendant - Appellant. OPINION COLE, District Judge: Defendant-Appellant Alex Ruiz appeals, on evidentiary grounds, his conviction for transporting illegal aliens in violation of 8 U.S.C. § 1324. Specifically, he argues that the district court abused its discr etion in admitting into evidence at his current trial a previous conviction he rece ived for that same crime. According to Ruiz, doing so violated both Federal Rule of Evidence 404(b) and the Constitution. Neither argument works. Because evidence of the prior conviction satisfies this c ourt’s four -part test for admissibility under Rule 404(b), the district court did not

4 USA V. R UIZ abuse its discretion in admitting it. And Ruiz forfeited his constitutional argument by failing to present it below, so we review that iss ue fo r plain error, which Ruiz cannot show. Thus, we affirm the district court. I. Background On June 10, 2023, Borde r Patrol Agents O rdoñez-Nuñez and Guzman were driving in separate unmarked vehicles along State Route (SR) 94 around Campo, C alifornia, less than two miles from the United States -Mexico bo rder. Th e agents noticed an older, white Honda Civic driving ten miles below the speed limit and weaving “in and out of lanes” along the highway. Agent Ordoñez-Nuñez grew suspi cious of the vehicle bec ause the driver and passenger kept lookin g at him through the window and side mirror, and the car was “sitting very low on the rear a xle” as if it carried extra weight in the back seat or trunk. After following the Civic for 15 – 20 minutes, Agent Ordo ñez-Nuñez ran a records check on it — the search included th e vehicle’s travel patterns, whether it had gone through any immigration checkpoints, and where it was registered. He learned the car was registered in La Mesa, over fifty miles away, and had no history of traveling in the area or through any checkpoints. Based on these results, the agent “requested for a marked Border Patrol unit to initiate a vehicle stop.” Shortly after, Ag ent Mallon drove up in a marked car, turned on the c ar’s lights and sirens, and attempted to pull over the Civic. Th e car, however, did not stop; rather, it continued at the same speed down the ro ad. At that point, the agents decided to deploy a vehicle im mobilization device, otherwise known as a spike strip. But the Civic swerved around it. Aft er that, a supervisor instructed the agents other th an Age nt Guzman, who had not turned on his

USA V. R UIZ 5 lights or siren, to dis continue their pursuit. But, while Agent Guzman continued following the Civic, he soon l ost sight of it for “approximately a minute or two.” When h e next saw the car, the Civic was “pulling back onto the road... two tires on pavem ent, two tires on dirt,” and four people were ten or fifteen yards off the roadway, running away. Agent Guzman immediately reported a “bailout” on his radio. A few mi nutes later, o fficers deployed a second spike strip. This ti me, the Civic hit it and soon came to a stop. Agents approached the vehicle and arrested Ruiz. Agent Mallon, meanwhile, searched the area where the “bailout” occurred and found shoe prints. The shoe prints led him 50 yards away from the highway to a tr ee in which four people were hiding. The four individuals were not U.S. citizens and did not have valid immigration documents, so Agent Mallon arrested all of them. II. Procedural History The government charged Ruiz with three counts of Transportation of Cert ain Aliens and Aiding and Abetting, in violation of 8 U.S.C. § 1324(a)(1)(A)(ii) and (v)(II). 1 To convict on the transportation charge, the government needed to prove: (1) the individuals named in the in formation were aliens, (2) those individuals were not lawfully in the United States, (3) “the defendant knew or acted in reckless disregard of the fact that the person specified in the coun t was not lawfully in the United S tates,” and (4) “the defendant knowingly transported or moved the person specified in the count to help him remain in the United States illegally.” The 1 Ruiz was charged with one count for each person who was traveling in his car. Jose Ma nuel Gomez Perez, the fo urth person in his car, was charged as a co-defendant, so he was not in cluded as one of the counts.

6 USA V. R UIZ parties stipulated th at the three people name d in the information were aliens in the United States illegally, satisfying the first two elements. The government’s burden at trial thus boiled down to proving Ruiz had the requisite knowledge as to both prongs three and four. 2 A. Ruiz’ s Prior Conviction Ruiz had pleaded guilty in an e arlier ca se to tra nsporting an alien in violation of 8 U.S.C. § 1324, although supposedly under a different subse ction. 3 That charge arose from Ruiz driving two minor females through a C alifornia port of entry and using false documents in early 2022. He pleaded guilty to the offense on August 19, 2022. In the run-up to the trial, the government indicated its intent to introduce th e earlier conviction, so Ruiz moved in limine to preclude that. But at a pre-trial h earing on the motions in limine, the district court ruled the conviction could come in under Federal Rule of Eviden ce 404(b) “to the extent that it would support the idea that Mr. Ruiz had 2 Ruiz argues th at the “only issue in dispute” was wheth er it was his Civic (as opposed to some other wh ite car also traveling down the road at th at same time) that was transpor ting the individuals. But while the d efense limited its ar guments to that issue, the governm ent still had to prove Ruiz’s k nowledge, which is an elemen t of the offense; therefo re, knowledg e was also at is sue. Un ited States v. Ramirez-Jimi nez, 9 67 F.2d 1321, 1325 – 26 (9th C ir. 1992). Defendant’s counsel acknowledged this at the motion in limine hearing, wh ere h e stated, “This is a straight -up knowledg e and intent case.” 3 Defendan t’s counsel s tated at the motion in limine hearing t hat the two offenses required different elements as they are different subsections of § 1324. The appellate br ief, however, states that Ruiz was convicted of 8 U.S.C. § 1 324(a)(1)(A)(ii) in th e cu rrent case, and that he pleaded guilty to a violation of 8 U.S.C. § 1324(a)(1)(A)(ii). Thus, the offenses were for violation s of the same subsection requiring the same elements.

USA V. R UIZ 7 knowledge that the individuals that he was transporting were indeed undocumented individuals and that h e had engaged in a plan to transport them within the United States.” 4 Based on that ruling, the pa rties agreed to redact certain prejudicial facts, suc h as that the prior case involved female minors a nd false documents. During the trial itself, the government raised the prior conviction several times, which the court almost always immediately followed with a limiting instruction. The government first m entioned it in its opening a rgument, at which time the district court inst ructed the jury that the conviction could b ear on “questions of knowledge and motive,” but that the jury should not consider it as evidence that the de fenda nt h as a bad character or pro pensity to commit crimes. Next, on day two, the government re ad into evidence a sti pulation that Ruiz had pleaded guilty to transporting an alien in 2022. In connection with reading that stipulation, the government also introduced and published reda cted copies of Ruiz’s plea agree ment, the transcript of the change of plea hearing, and the judgment. Once again, the district court gave a long limiting instruc tion to only consider the prior conviction to decide: “one, whether the defendant had the knowledge or intent nece ssary to commit the crimes c harged in the information in this case; and, two, whether the defendant did not commit the acts for which he is on trial by accident or by mistake.” The government also published the a bove-mentioned documents to the jury during Agent Guzman’s testimony. At the clos e of trial, th e dist rict court again inst ructed the jury to only consid er the prior conviction for questions of 4 The district court also adm itt ed the prior conv iction under FRE 60 9, but this is irrelevan t because Ruiz did not te stify.

8 USA V. R UIZ “the defendant’s int ent, knowledge, abs ence of mistake, or absence of accident a nd for no other purpo se.” He specifically instructed the jury that it “may not co nsider this evidence as evidence of guilt of the crime for which the defendant is now on trial.” In its closing, the government highlighted how the prior conviction showed a lack of mistake or accident. Th e defense, by contrast, argued that there are “important differences” b etween the prior and instant case, and that it ca n only be used for limited purposes, but “there’s really only one reason that that is in evidence”— i.e., the government wanted the jury to use i t for illicit propensity purposes to conclude Ruiz was guilty of once again engaging in the same type of conduct. Beyond that, the district court elected not to allow the redacted documents to go back with the jury during deliberations in orde r to limit any “undue emphasis.” B. The Government’ s Other Evidence at T rial Apart from the prior conviction, the government presented substantial e vidence about Ruiz’s conduct that formed the basis for the current charges. Agents Ordoñez- Nuñez, Haynes, Mallon, and Guzman all testified. Three of the four identified Ruiz as the vehicle driver. The jury also watched body-worn camera footage and saw portions of the second spike strip, the Civic c oming to a rest, and the driver (Ruiz) exiting the car. It also saw screenshots from Agent Mallon’s body -worn camera depicting the four people in the tree. Perhaps t he “star witness” was Jose Manuel Gomez Perez, one of the individuals in the car and Ruiz’s one-time co -defendant. Gomez had pleaded guilty the week before Ruiz’s trial. Gomez testified at Ruiz’s trial that Gomez was a foot guide for the group, leading them from Mexico into

USA V. R UIZ 9 the United States. Gomez further testified that he used WhatsApp to coordinate with others the group’s entry into the United States. In that regard, he testified he was instructed to wait for what he describe d as a “ white car” and a “Hond a” to pick up the group. While Gome z could not identify the driver, he testified that the driver: (1) called Gomez by his nickname, “Chiapas”; (2) told the group to bend down in the vehicle because they were getting caught; and (3) finally told them to “get out” on the s ide o f the road before they hid in the tree. The government argued that these statements showed that the Honda driver (who the government a rgued was Ruiz) did not randomly pick up passengers along the road, but instead had bee n sent to collect the specific group of illegal aliens and trans port them further into the United States. Agent Guzman also testified that another member of the group, Miguel, sent his coordinates in the WhatsApp group text conversation referenced above. The government then introduced into evidence a map showing that these coordinates were not far from where Border Pat rol agents started following Ruiz and finally stopped him. The defense did not offer any evidence. After closings, the jury began de liberating at 1:00 pm. I t returned a verdict at 2:17 p.m. The jury convicted Ruiz on all three counts. The district court sentenced Ruiz to thirty- three months of imprisonment and three years of supervised release. STANDARD OF REVIEW We review de no vo wh ether the challenged evidence falls within the scope of “other crimes” evidence for Rule 404(b) purposes. United States v. Soliman, 813 F.2d 277,

10 USA V. R UIZ 278 (9th Cir. 1987). If the evidence does not fall within that scope (e.g., if the a lleged “other crime” is “inextricably intertwined” with the current charge such that it is not really a separate offense), the analysis ends, and Rule 404(b) does not prevent admission. Id. at 279. If, on the other hand, the evidence is properly characterized as “other crimes” evidence, then we review for abuse o f discretion the dist rict court’s decision to admit the evidenc e under Rule 404(b)(2). United States v. Ramirez-Robles, 386 F.3d 1234, 1242 (9th Cir. 2004). If Rule 404(b) do es not preclude admission, we separately consider, under Rule 403, whether any unfa ir prejudice arising from admitt ing the evidence subst antially outweighs its probative value. United Stat es v. Chea, 231 F.3d 531, 534 (9th Cir. 2000). We review that determi nation for abuse of discretion. United States v. Flores-Blanco, 623 F.3d 912, 919 (9th Cir. 2010). ANALYSIS I. Rule 404(b) did not bar admiss ion of Ruiz’s prior conviction. Rule 404(b) prohibits using evidence of a previous crime “to prove a person’s character in order to show that on a particular occasion the person acted in accordance with the character.” Fed. R. Evid. 404(b)(1). Such evidence is admissible, however, to prove “another purpose,” including “motive, opportunity, intent, preparation, plan, knowledge, identity, absence of mistake, or lack of accident.” Fed. R. Evid. 404(b)(2) (emphas es added). We have developed a four-part test to decide when a prior bad act is admissible: “(1) the evidence tends to prove a material poi nt; (2) the other act is not too remote in time; (3) the evidence is sufficient to support a finding that defendant commi tted the

USA V. R UIZ 11 other act; and (4) (in certain cases) the act is similar to the offense charged.” United Stat es v. Romero, 282 F.3d 683, 688 (9th Cir. 2002). The prior conviction satisfies all four prongs. A. The prior conviction pr oved a material point. The first element of th e four-part test to determine admissibility asks whether “the evidence tends t o prove a material point.” Id. To convict Ruiz, the g overnment needed to prove that he knew the individuals at issue were not lawfully in the United States, and that he knowingly transported them to help them remain in the United States illegally. 8 U.S.C. § 1324(a)(1)(A)(ii); see supra Procedural History. Thus, Ruiz ’s knowledge wa s a material element the government needed to prove. Ramirez- Jiminez, 967 F.2d at 1325 – 26. We ha ve repeatedly affirmed using prior stops, arrests, and convictions for transporting aliens to help show the same defendant’s knowledge in later ca ses. See, e.g., United States v. Holley, 493 F.2d 581, 584 (9th Cir. 1974) (prior stop was relevant because “knowledge was a critical issue”); United States v. Espinoza, 578 F.2d 224, 227 – 28 (9th Cir. 1978) (prior act and pend ing charges were admissible where “central iss ue... was t he knowledge and intent ”); United States v. Winn, 767 F.2d 527, 529 – 30 (9th Cir. 1985) (prior conviction “shows that appellant had knowl edge of the smuggling operation”); Flores-Blanco, 623 F.3d at 919 n.4 (testimony of prior invol vement tende d to prove knowledge, intent, and plan). United States v. Longoria is particularly instructive. 624 F.2d 66, 68 – 69 (9th Cir. 1980). There, Border Patrol agents followed a taxicab d river, Longoria, near the Mexican border when he appeared to have illegal aliens in his car. Id. at 68.

12 USA V. R UIZ Agents then stopped and arre sted Longoria. Id. At trial, the central issue was whether Longoria knew the people in his cab were illegal aliens. To prove that element, the government introduced evidence of a prior conviction for transporting illegal aliens, in which Longoria had likewise driven aliens from the bor der to a motel. Id. at 68 – 69. Much like here, Longoria appe aled, challenging the trial court’s admission of th at prior conviction on Rule 404(b) grounds. Id. at 69. But we rejected that argument, holding that “evidence of a prior similar offense is highly relevant and admissible to show the requisite knowledge, criminal intent, and lack of innocent purpose.” Id. Just as in L ongoria, the main element the gov ernment needed to prove at trial here was whether Ruiz knew he was transporting illegal aliens. The district court admitted the prior conviction to prove such knowledge, a material element. Se e Holley, 493 F.2d at 584; Longoria, 624 F.2d at 69. The government in its closing argument also argued that the prior conviction pro ved a lack of accident or mistake. That is a permissible pur pose, as well. Under Longoria, the government can us e prior convictions to p rove “ lack of innocent purpose.” 62 4 F.2d at 69. Specifically, the evidence provided a basis for the jury to conclude that Ruiz was not involved by mistake. At bottom, the government needed to show that Ru iz was not a random driver wh o happened to pick up hitchhikers who happened to be illegal aliens. The prior conviction tended to prove that material fact.

USA V. R UIZ 13 B. The prior conviction was not too r emote in time. The second element to determine admissibility of prior bad ac ts is whether the al leged bad act is too remote in ti me. Romero, 282 F.3d at 688. Here, the earlier illegal c onduct — transporting aliens — occurred in February 2022, and Ruiz was convicted of that crime on August 19, 2022. His conviction for the instant offense, meanwhile, oc curre d on October 18, 2023, so the complete timeline is less than two years. Th at falls well w ithin durations we have approved. United States v. Spillone, 879 F.2d 514, 519 (9th C ir. 1989) (affirming admission of conviction from more than ten years before trial); United States v. Johnson, 132 F.3d 1 279, 1283 (9th Cir. 1997) (finding prior bad acts from thirt een years before were admissible). C. There is sufficient evidence that the prior crime occurr ed. The third element is whether there is sufficient evidence that the e arlier bad act actually happened. Romero, 282 F.3d at 688. This prong imposes a “low threshold. ” Id. This c ourt has held that a defendant’s conviction for the prior offense more than satisfies it. United States v. Arambula- Ruiz, 987 F.2d 599, 603 (9th Cir. 1993) (“[T]he fact that [the defendant] was convicted of the prior drug offense is sufficient proof that the defendant committed the prior act.”). Not only was Ruiz convicted of the of fense of transporting aliens, but he sti pulated that he had plead ed guilty to it. In other words, he admitt ed he had committed the crime. That easily satisfies the third prong.

14 USA V. R UIZ D. T o the extent similarity is needed, the pri or conviction is similar to t he offense charged. The fourth element asks whether the prior bad act is sufficiently similar to the instant offense, but this element only applies “in certain cases.” Romero, 282 F. 3d at 688. For example, a prior conviction need not be a similar offense if offered to prove knowledge, “as long as the prior act was one which would tend to make the existence of the defendant’s knowledge more prob able than it would be without the evidence.” Ramirez-Jiminez, 967 F.2d at 1326; but see United States v. Mayans, 17 F.3d 1174, 1181 (9th Cir. 1994) (stating the last element of the four-part test as “(4) (in cases where knowledge and intent are at issue) the act is similar to the offense charged” (citation omitted)). By contrast, if the evidence is offe red to prove “identity, modus operandi, or absence of mistake or a ccident,” then similarity is required. Ramirez-Ji minez, 967 F.2d at 1326 (quoting United States v. Bailleaux, 685 F.2d 1105, 1110 n.1 (9th Cir. 1982)). “ The reason for this is that simil arity, like proximity in time, is not a prerequisite having independent force, but rather a factor pertinent to rational appraisal of the probative value of the evidence in relation to the purpose fo r which it is being off ered.” Id. Here, the district court ini tially admitted the evidence “to the extent that it would support the idea that Mr. Ruiz had knowledge that the individuals he was transporting were indeed undocumented i ndividuals, ” an account on which similarity is perhaps not required. At trial though, the purposes expanded to in clude motive, intent, and lack of accident or mistake, which can impose a similarity requirement.

USA V. R UIZ 15 Ultimately, though, it matters little whether this prong applies, as it is satisfied. But why that is so merits some additional explanation. At a high level, of course, both this case and the earlier conviction involve transporting illegal aliens in violation of § 1 324, with Ruiz acting as the driver in Southern California. So on that telling, they seem similar. But viewed with more g ranular ity, differences emerge. For example, Ruiz was apprehended at dif ferent places; in the earlier case, he w as arrested at a California port of entry, while here agents stopped him on a rural road several miles into the United States. And the nature of the offense w as arguably different. Bef ore he had transported two female minors and did not atte mpt to conceal them, instea d he attempt ed to use false documents. Here, he concealed four adult men and told them to “get out” a fter Border Patrol first attempted to stop him. 5 So it matters how we go about assessing similarity. One approach th is court has used in answering that question is to compare the magnitude of the differences in the crimes in the current case to the diffe rences that th is court has approved as “similar” in past cases. See, e.g., United States v. Herrera-Medina, 609 F.2d 376, 380 (9th Cir. 1979) (finding that the prior arrests a nd offense c harged ther e we re sufficiently similar because they were mor e similar than the prior acts at iss ue in Espinoza and Holley, cases in which this court had upheld admissibility of prior bad acts evidence). Applying that framework, Ruiz’s current crime and his past conviction are similar. 5 Defense cou nsel also argued below that an other difference is that Ruiz pleaded gu ilty in th e prior case an d was “willing to admit wh ere he’ s wrong,” but in this case, he did not. But this is no t a difference in the circumstances of the offense or factual basis fo r his arrest in that case.

16 USA V. R UIZ For example, in Holley, we upheld admission of Holley’s prior arrest fo r tr ansporting illegal aliens to prove Holley’s knowledge that his taxicab passenge rs in the cur rent case were illegal aliens. 493 F.2d at 584. In both cases, Holley was the driv er, but, much like here, the specific details varied —“the number, age, sex, and attire” of the aliens was different. Id. at 585 (Hufstedler, J., dissenting). Further, in the earlier case, Holley picked up th e couple near his garage in his private car. Id. But in the later c ase, he picke d up four men in his taxic ab a fter re ceiving a radio call from the company dispatcher. Id. Despite these differences, we held that the district court did not abuse its discretion in admitting the prior arrest as “prior similar conduct.” Id. at 584. Similarly, in Espinoza, we upheld admission of Border Patrol a gents’ testimony about their previous surveillance o f the defendants before the arrest leading to the case at trial. 578 F.2d at 226 – 28. Earlier, Border P atrol agents had observed the defendants in their truck pull next to a van, and that van wa s later found with 27 aliens inside. Id. at 226 – 27. The conduct at issue at trial, by contrast, involved an illegal alien calling one defendant, that defendant picki ng him up from a gas station, driving him to the defendant’s house, and the other defendant arriving at the house and picking up the illegal alien, where Border Patrol agents then stopped them. Id. A s we described in a later case, “ the defendants in [Espinoza ] had not, in the prior incident, picked up illegal aliens. The most that a jury could hav e inferred was that they had arranged to have another person pick up the aliens.” Herrera-Medina, 609 F.2d at 380. Despite these differences, we found the acts sufficiently similar to allow admission under Rule 404(b). Espinoza, 578 F.2d at 228. The details here are more sim ilar than in Espinoza. There, as noted, the defendants had been the drivers one

USA V. R UIZ 17 time, but only arrange d a pick-up the other. 578 F.2d at 226 – 28. Here, Ruiz acted as the driver in both the cases. True, the number, sex, and age of the immigrants differed, but Holley rej ect ed th e idea that this prevents a finding of similarity. 493 F.2d at 585 (Hufstedler, J., dissenting). Further, both offenses occurr ed in the same region along the border in Southern California. Thus, the prior conviction is sufficiently similar to the instant offense t o support admissibility. In sum, the prior conviction satisfies each prong of the test for Rule 404(b) — it tended to prove the mate rial point of knowledge, two years is not too remote in time, the stipulation and redacted documents provided sufficient evidence of the prior bad a ct, and the prior crime was sufficiently sim ilar to the offense charged. Therefore, the district court did not abuse its discretion in admitting the prior conviction under Rule 404(b). The Defendant urg es a different result, arguing that the prior conviction was inadmissible for failure to meet the third prong of the Rule 404(b) test — whether there was sufficient evidence the prior bad act had occurred. See United States v. Bailey, 696 F.3d 794, 799 (9th Cir. 2012); United States v. Wells, 87 9 F.3d 900, 914 (9th Cir. 2018). I t is true that, in Bailey, we held that the district court had e rred in admitting a prior civil SEC complaint in a later action as evidence that the prior o ffense had occurred. 696 F.3d at 799. Specifically, we he ld that when the sole evidence that a prior bad act occurred is a complaint, that does not satisfy the third prong of the ad missibility test. But that is because a complaint includes only allegations, not proof. Id. Here, by contrast, Ruiz pleaded guilty to, and was convict ed of, th e prior offense. That more than suffices to show the offense occurred.

18 USA V. R UIZ Ruiz ’s brief does not even meaningfully argue otherwise. While Ruiz characterizes his challenge as directed at the third element, Ruiz, based on Bailey, really contests the similarity element — prong four. As he puts it in his brief, “ the bare fac t of a prior § 1324 conviction does not establish that he committed an act like the on e charged here.” (Emphasis added). That fails for the above-noted reasons relating to prong four. Wells does not help him either. 879 F.3d 900. There, the district c ourt first admitted expert testimony regarding a criminal “profile,” and the government then argued the defendant’s characteristics fit that profile. Id. at 914. But the use of “profile” testimony raises questions u nder Rule 404(a)(1), so th e analysis on that front is entirely irrelevant to the Rule 404(b) challenge here. Id. at 920 – 21. To be sure, the district court also had admitted various other prior b ad acts that formed the b asis for t he profile testimony, which did bring Rule 404(b) into play. But much of th e ana lysis of that issue was limited t o whether the evidence was even subject to Rule 404(b) in light of the inextricably intertwined exception. Id. at 925. The scope of that exception is irrelevant h ere, though, as no party raised, nor did the district court rely on, this exception in determining admissibility. And beyond that, Wells a ffirmed admitting most of the prior bad acts, except for one conviction, to prove mot ive under Rule 404(b). Id. at 929. Specifically, the government used the prior bad acts to explain why the defendant wanted to murder his coworkers — i.e., classic motive evidence. Id. Here, by contrast, while the dist rict court mentioned the prior conviction could be used to prove “knowle dge and motive,” the government did not use Ruiz’s conviction to argue motive, but only to argue that he knew that the individuals

USA V. R UIZ 19 were in the United States illegally. Therefor e, Wells is not instructive here. In sum, the district court did not abuse its discretion in admitting the prior conviction under Rule 404(b). II. Ruiz’s prior conviction should not be exc luded under Rule 403. Because there was no error under Rule 404(b), we must consider whether admitting the prior conviction complies with Rule 403’s balancing test. “If th e eviden ce meets [the four- part] test under Rul e 404(b), ‘the [district] c ourt must then decide whether th e probative value is su bstantially outweighed by the prejudicial impact under Rule 403.’” Chea, 231 F.3d at 534 (quoting United States v. Nelson, 173 F.3d 1094, 1107 (9th Cir. 1998)). But, even if a district court does not explicitly men tion R ule 403, we “wil l uphold admission of the evidence when it is clear from t he record that the court impli citly made the necessary finding.” Ramirez-Jiminez, 967 F.2d at 1326. The record shows that the district court implicitly considered th e balan cing question. At the mot ion in li mine hearing, Ruiz argued t hat certain facts about the prior conviction (i.e., that it involved minor females and false documents) were overly prejudicial and, at minimum, needed to be redacted. The district court agreed that those facts would be overly prejudicial and “wouldn’t move the ball up the field,” so the prior conviction should be “sanitized.” The government agreed to redact the documents. Additionally, the district court did not allow testimony from the ag ent involved in the prior conviction because it would be unnecessary on top of the guilty plea and other documents. Furthermore, the district court did not let the documents go back with the jury along with the other

20 USA V. R UIZ exhibits be cause it would give “undue emphasi s” to the conviction. Taken tog ether, this conduct shows that, even though the district court may not have explicitly mention ed Rule 403, it weighed the probative value and un fair prejudice in deciding how to allow the government to introduce the evidence. Relatedly, the district court did not abuse its discretion in performing this b alancing. Rule 403 di rec ts the court to exclude evidence “if it s probative value is su bstantially outweighed by a danger of... unfair prejudice.” Fed. R. Evid. 403. Specifically, the prejudice must be unfai r, meaning it has “an undue tende ncy to suggest decision on an improper basis, commonly, though not necessarily, an emotional one.” Old Chief v. United States, 519 U.S. 172, 180 (1997). The probative value in a knowledge ca se, on the other hand, is “measured by its tendency to make the existence of [Ruiz’s] kn owledge or intent more probable than it would be without the evidence.” Ramirez-Jiminez, 967 F.2d at 1327. Ruiz’s prior conviction for tra nsporting illegal a liens makes it more p robable that he had knowledge that the individuals in his car were present illega lly and that he knowingly transported t hem to help them remain in the United States. This prior conviction is unlikely to cr eate an emotional or otherwise unfairly prejudicial response, especially since the parties redacted the facts concerning female minors and false birth certificates. “Rather, it is prejudicial only to th e extent that it tends to prove the fact justifying its admission, namely that appel lant had knowledge of his cargo of illegal aliens.” Id. In other words, it is fairly, not unfairly, pre judicial. Beyond that, the district court gave repeated limiting instructions about the proper purpose of the prior conviction each time the governme nt

USA V. R UIZ 21 raised it, further minimizing any risk of unfair prejudice. Flores-Blanco, 623 F.3d at 920. Accordingly, we hold that any risk of unfair prejud ice did not substantially outweigh the probative value of t he prior conviction, meaning the district court did not abuse its discretion at this step in admitting the prior conviction. III. Ruiz did not raise the constitutional question in the lower court, so we review for plain error, which Ruiz has not shown. Separately, R uiz argu es that admitting the prior conviction viol ated both due process and his S ixth Amendment right to a fair trial. Ruiz, howe ver, did not raise these constitutional issues below. Accordingly, we review for plain error. See United States v. Perez, 116 F.3d 840, 846 (9th Cir. 1997) (en banc); United Stat es v. Depue, 912 F.3d 1227, 1232 (9th Circ. 2019) (en banc). Ruiz has not shown that the dist rict court plain ly err ed under e ither the due process clause or the Sixt h Amendment in admitting the prior acts evidence. He only argu es that a court violates those constitut ional provisions by admit ting such evidence purely for propensity purposes. As he states it, “propensity evidence is constitutionally inadmissible.” And he acknowledges tha t the Supreme Court has twice held that admission of p rior acts evidence does not violate due process where it is not offered as general propensity evidence. See Dowling v. United States, 493 U.S. 342, 353 – 54 (1990) (no due process violation where eviden ce “was at least circumstantially valuable in proving petitioner’s guilt” for reasons apart from p ropensity); Spencer v. Tex., 385 U.S. 554, 556 (1967) (upholding habitual offender statute that required state to introduce proo f of prior conviction to establish enhancement, s ubject to limiting instruction that

22 USA V. R UIZ “such matters were not to be taken into account in assessing the def endant’s guilt or innocen ce under the current indictment ”). As described above, the United S tates did not rely on the prior acts evidence as propensity evidence. Rather, it used the evidenc e to prove Ruiz’s knowledge. Moreover, as noted, the probative value of the evidence in establishing that knowledge was not substantially outweighed by any unfair prejudice. In sum, the fa ctual predi cate for Ruiz’s argument (that the evidence came in solely for propensity purposes) is wrong. Accordingly, Ruiz fails to establish tha t the trial court committed constituti onal plain error in admitting that evidence. And, because the evidence was not admi tted for propensity purposes, we need not, and thus do not, decide whether admitting evidence purely for such purposes would violate the Constituti on. See Dobbs v. Ja ckson Women’s Health Org., 597 U.S. 215, 348 (2022) (Roberts, C.J., concurring) (“If it is not necessary to dec ide more to dispose of a case, then it is necessary not to decide more.” (emphasis original)). CONCLUSION For the foregoing re asons, we aff irm the judgment of the district court.