[Frank Ettin]

Originally Posted by HiBC

...The MedPot card pretty much documents a person as a user.

Or at least is probably cause to believe he is a user. See the discussion of Wilson v. Lynch, below.

Originally Posted by SonOfScubaDiver

You'd think that a conviction would have to be on one's record before they'd actually be breaking federal gun laws.

One federal crime would be the possession/use of marijuana, and if one is prosecuted for that he will indeed need to be convicted in court before he goes to jail. The violation of federal guns laws would be being a prohibited person in possession of a gun, and one would need to be prosecuted and convicted of that before going to jail.

But any use of marijuana is unlawful under federal law, and guns in the possession of someone who has been identified as a user of marijuana are contraband and can not be possessed by that person. So once it's determined that someone is a user of marijuana he can't lawfully keep his guns.

Originally Posted by steve4102

...Read, Wilson v. Lynch....

Yes, let's. It's really a very narrow decision.

One reason I'm going into this case in some detail is that I've seen many people (but not Steve here -- he knows better) misinterpreting the case to say that while a user of marijuana can't buy guns, he can keep the ones he has. That's wrong, and I'll explain why it's wrong and what Wilson really means.

The Ninth Circuit's ruling in Wilson does not abrogate or affect in any way the existing law that an unlawful user of a controlled substance is prohibited under federal law from possessing a gun or ammunition. So an unlawful user of a controlled substance is not only prohibited from buying guns or ammunition, but also may not lawfully keep any guns he has.

1. Wilson v. Lynch (Ninth Circuit, No. 14-15700, 2016) did not address in any way whether it is lawful for an unlawful user of a controlled substance to possess a gun or ammunition.
   
   
   1. The Ninth Circuit had already ruled that 18 USC 922(g)(3), making it illegal for an unlawful user of a controlled substance to possess a gun or ammunition, is constitutional and applicable to an unlawful user of marijuana (U.S. v. Dugan, 657 F.3d 998, (9th Cir., 2011) at 999):

      ...We consider the constitutionality of 18 U.S.C. § 922(g)(3), which makes it illegal for “any person ... who is an unlawful user of or addicted to any controlled substance ... to ship or transport in interstate or foreign commerce, or possess in or affecting commerce, any firearm or ammunition; or to receive any firearm or ammunition which has been shipped or transported in interstate or foreign commerce.” Reviewing de novo United States v. Vongxay, 594 F.3d 1111, 1114 (9th Cir.), cert. denied, ––– U.S. ––––, 131 S.Ct. 294, 178 L.Ed.2d 193 (2010), we uphold the statute against this Second Amendment challenge.....

   2. Ms. Wilson did not challenge 18 USC 922(g)(3), and the issue of the application of 18 USC 922(g)(3) to her was not even considered.
      
      
   3. 18 USC 922(g)(3) is the federal law which makes it illegal for anyone in one of several classes of persons to possess a gun or ammunition. But Wilson did not challenge that statute, nor did she have standing to do so (Wilson, slip op., at 9-10, footnotes omitted):

      ...First, as appellant’s counsel conceded at oral argument, Wilson lacks standing to challenge 18 U.S.C. § 922(g)(3). Standing requires, among other elements, a “concrete and particularized” injury that is “actual or imminent, not conjectural or hypothetical.” Lujan v Defs. of Wildlife, 504 U.S. 555, 560 (1992) (internal quotation marks omitted). Section 922(g)(3) criminalizes possession or receipt of a firearm by a unlawful drug user or a person addicted to a controlled substance. Wilson has not alleged that she is an unlawful drug user or that she is addicted to any controlled substance. Nor has she alleged that she possessed or received a firearm. Accordingly, Wilson has not alleged that § 922(g)(3) has injured her in any way. For the same reasons, she also has not shown a “genuine threat of imminent prosecution” under § 922(g)(3), as is generally required of plaintiffs raising pre-enforcement challenges to criminal statutes outside the First Amendment context. San Diego Cty. Gun Rights Comm. v. Reno, 98 F.3d 1121, 1126 (9th Cir. 1996) (internal quotation marks omitted). Accordingly, we affirm on the ground of lack of standing the district court’s dismissal of Wilson’s claims concerning § 922(g)(3)....

   
   
2. Wilson addressed only whether someone with a medical marijuana card may be prevented from buying a gun.
   
   
   1. Ms. Wilson's challenge, and therefore the opinion in Wilson, was narrow (Wilson, slip op. at 10):

      ...Wilson does have standing, however, to raise her remaining claims challenging 18 U.S.C. § 922(d)(3), 27 C.F.R. § 478.11, and the Open Letter. Wilson alleges that § 922(d)(3)’s ban on sales of firearms to individuals whom sellers have reasonable cause to believe are drug users, along with the regulations and guidance implementing this ban, prevented her from purchasing a firearm....

   2. 18 USC 922(d) reads, in pertinent part:

      (d) It shall be unlawful for any person to sell or otherwise dispose of any firearm or ammunition to any person knowing or having reasonable cause to believe that such person—

      ...
      
      (3) is an unlawful user of or addicted to any controlled substance (as defined in section 102 of the Controlled Substances Act (21 U.S.C. 802));...

   3. Thus 18 USC 922(d) does not address the legality of a person within a prohibited class possessing a gun or ammunition. It only addresses the legality of someone transferring a gun or ammunition when one knows or has reasonable cause to believe that the transferee is a prohibited person.
      
      
   4. Therefore, the Ninth Circuit in Wilson considered only the validity of 18 USC 922(d) prohibiting transfer of a gun to someone the transferor knows or has reasonable cause to believe is a prohibited person together with ATF guidance to FFLs based on that statute.
   
   
3. Therefore, a person who is an unlawful user of a controlled substance violated federal law (specifically 18 USC 922(g)(3)) by possessing a gun or ammunition and may not lawfully have a gun or ammunition in his possession.