UPDATE: If you make this argument, be sure to make the federal constitutional argument for merger as well. That argument is:
The Fifth Amendment's prohibition on double jeopardy protects against being punished twice for a single criminal offense. U.S. Const. amend. V.; Brown v. Ohio, 432 U.S. 161, 165, 97 S. Ct. 2221, 53 L. Ed. 2d 187 (1977). When multiple sentences are imposed in the same trial, "the role of the constitutional guarantee is limited to assuring that the court does not exceed its legislative authorization by imposing multiple punishments for the same offense." Brown, 432 U.S. at 165. When a defendant has violated two different criminal statutes, the double jeopardy prohibition is implicated when both statutes prohibit the same offense or when one offense is a lesser included offense of the other. Rutledge v. United States, 517 U.S. 292, 297, 116 S. Ct. 1241, 134 L. Ed. 2d 419 (1996).
United States v. Davenport, 519 F3d 940, 943 (9th Cir. Mont. 2008)
The reason why is that it would trump any state constitutional arguments that the prosecutor might make for keeping the offenses separate.
In a previous essay, I raised the possibility that PCS would - contrary case law notwithstanding - merge into DCS, if the DCS also alleged possession of a substantial amount of the controlled substance (which it would likely do in a CDO or substantial quantities case). The argument was straightforward: an enhancement fact (such as "more than 8 grams of cocaine") is considered an element for the purposes of determining if a crime is a lesser-included offense. See State v. Riehl, 188 Or App 1 (2003)(finding that robbery in the second degree based on representation of a deadly or dangerous weapon is not a lesser-included offense of robbery in the first degree based on being armed with a deadly weapon, unless the state has also alleged the sentence enhancement factor of "use or threatened use of a firearm.").
Let's take this one step further. Your client is charged with Unlawful Use of a Weapon. He is also charged with Felon in Possession of a Firearm, and the gun minimum (use or threatened use of a firearm) is alleged on both counts.
By alleging the gun minimum on the Felon in Possession, hasn't the state simultaneously alleged the elements of "unlawful use of a weapon"? In other words, is there any conceivable way a defendant could be guilty of "use or threatened use of a firearm" but not guilty of UUW? (Let's leave aside this issue for now.)
A crime is a lesser-included offense of another crime as a matter of law if either of two circumstances exist: "(1) the elements of the lesser offense necessarily are included in the greater offense because the elements of the former are subsumed in the latter; or (2) all of the elements of the lesser offense are expressly set forth in the accusatory instrument." State v. Lee, 174 Or App 119, 125, 23 P3d 999, rev den, 332 Or 559 (2001).
In this hypothetical, is UUW now a lesser-included of Felon in Possession (with a firearm), per State v. Riehl? And if it is, wouldn't they merge, so that Felon in Possession is the only one left standing?
This possibility came in a discussion with an attorney who has sentencing later this week. It shows again the value of communication between defense attorneys. Even casual conversations can lead to inspiration.
That said, this analysis is "back of the envelope" at this time of night. I haven't worked it all the way through. But if it's an issue you're facing, think about giving it a shot. It would be one less UUW conviction on your client's record.