dissenting:
I agree that the evidence was sufficient to sustain the verdict and that there was probable cause to search Vizcarra-Martinez’s car. However, I do not agree that it was prejudicial error to admit the small amount of methamphetamine that Vizcarra-Martinez had on his person when he was arrested.
Often we have even said that possession or use of a drug on a prior occasion is relevant to show the knowing possession of drugs on a second occasion. See United States v. Santa-Cruz, 48 F.3d 1118 (9th Cir.1995); United States v. Hegwood, 977 F.2d 492 (9th Cir.1992), cert. denied, — U.S. -, 113 S.Ct. 2348, 124 L.Ed.2d 257 (1993); United States v. Milner, 962 F.2d 908 (9th Cir.), cert. denied, — U.S. -, 113 S.Ct. 614, 121 L.Ed.2d 548 (1992); United States v. Marshall, 526 F.2d 1349 (9th Cir.1975), cert. denied, 426 U.S. 923, 96 S.Ct. 2631, 49 L.Ed.2d 376 (1976); United States v. Perez, 491 F.2d 167 (9th Cir.), cert. denied, 419 U.S. 858, 95 S.Ct. 106, 42 L.Ed.2d 92 (1974). It is true that those cases involved prior and current possession of drugs, whereas this ease involves possession of a drug and of a precursor chemical. It is also true that a person could possess a drug and not know what chemicals went to make it up. Still, it is also true that a person could possess a little cocaine and still not know what heroin was. But see Marshall, 526 F.2d at 1360-61; (possession of cocaine could lead to inference of knowledge of heroin) Perez, 491 F.2d at 171-72 (same). And a person could have used drugs and still not know that a package had drugs in it. But see Hegwood, 977 F.2d at 497 (prior use of cocaine is relevant to knowledge, intent, absence of mistake). And a person could have used drugs and still not have conspired to distribute them. But see Santa Cruz, 48 F.3d at 1120 (prior possession of cocaine relevant to knowing participation in drug deal 12 weeks later); Milner, 962 F.2d at 912-13 (evidence of drug use relevant *1517to show person conspiring to distribute drug). Coulds are interesting, but they do not make evidence irrelevant or inadmissible. So it is here.
Another concept militates against a determination that the admission of the methamphetamine was unfairly prejudicial. We have not been overly prissy about making sure that a defendant knew exactly what drugs he was transporting. We have considered one combination of chemicals to be as good as another. So if a person thought he had marijuana, but had cocaine or heroin, he could be prosecuted for cocaine or heroin possession. See United States v. Ramirez-Ramirez, 875 F.2d 772, 774 (9th Cir.1989); United States v. Lopez-Martinez, 725 F.2d 471, 475 (9th Cir.), cert. denied, 469 U.S. 837, 105 S.Ct. 134, 88 L.Ed.2d 74 (1984). Cf. United States v. Davis, 501 F.2d 1344, 1345-46 (9th Cir.1974) (psilocybin mushrooms versus LSD). It is easy to infer that Vizcarra-Martinez knew he was illicitly transporting a chemical substance of some kind. His clandestine activity, his driving to the pickup place with one of the major co-conspirators in tow, his lies, his threats, and his pay all tended to show that he was not just some poor unknowing wretch who was transporting water or gasoline for all he knew. We cannot get inside his head to determine whether he thought he was transporting methamphetamine itself or something to make methamphetamine with. But we can discount his claim that he had no idea at all about what it might be.
Vizcarra-Martinez’s possession of methamphetamine was relevant to undercut his total ignorance argument and it did add a piece to the puzzle, even though what the picture was going to be was pretty clear already.
Therefore, I respectfully dissent.