An interesting decision (Jennings v. Mukasey) that was just uploaded to Lexis, though it was handed down two and a half months ago:

Plaintiff, Bruce L. Jennings, has brought suit seeking, inter alia, a judgment from this Court declaring the status of his rights under 18 U.S.C. § 922(g)(9), which prohibits the possession of firearms by those convicted of a misdemeanor crime of domestic violence. Specifically, Plaintiff asks this Court to determine whether a 1985 State court conviction for misdemeanor domestic violence prohibits Plaintiff from lawfully possessing a firearm under federal law, notwithstanding the fact that the conviction has been expunged or otherwise set aside by the State court. Because his conviction has been expunged, Plaintiff alleges that 18 U.S.C. § 921(a)(33)(B)(ii) excepts him from § 922(g)(9)’s prohibition against firearm possession.

Plaintiff has further alleged that Defendants have threatened him with criminal prosecution if he should decide to possess a firearm; that this threat of prosecution infringes upon the exercise of his Second Amendment rights; and that Defendants’ threatened prosecution has precluded him from obtaining employment in the firearms industry, in which he has had approximately thirty (30) years of experience in evaluating various designs of handguns for licensed firearm dealers....

Defendants argue that by seeking a declaration that the State court judgment setting aside and expunging Plaintiff’s conviction for misdemeanor domestic violence effects § 921(a)(33)(B)(ii)’s exception to § 922(g)(9), Plaintiff has asked this Court to “restrain the prosecutorial authority of the United States.” As a result, Defendants contend that this Court is without subject matter jurisdiction to hear Plaintiff’s case.

While the Supreme Court has observed that the executive branch has “exclusive authority and absolute discretion to decide whether to prosecute a case,” and the Fifth Circuit has noted that “courts are not to interfere with the free exercise of the discretionary powers of the attorneys of the United States in their control over criminal prosecutions,” this discretion can give way where important constitutional rights are at stake....

Assuming, as the Court must at this stage in the proceedings, that Plaintiff’s conviction was duly expunged, it seems that he would clearly fall within the statutory exception in § 921(a)(33)(B)(ii) and would not be subject to prosecution under § 922(g)(9). Furthermore, in light of District of Columbia v. Heller, Plaintiff raises a viable claim that the violation of his Second Amendment right to bear arms also deprives him of the right to earn a livelihood. Taken together, the Court concludes that Plaintiff’s allegations fall within the very limited exception to the general principle of immunity, that Plaintiff is otherwise without an adequate remedy at law, and that Plaintiff would suffer irreparable harm if not permitted to proceed in the instant action....

Where the plaintiff’s suit does not seek to impose upon the fisc, but only to declare the status of fundamental constitutional rights, the requirement of a statutory waiver [of sovereign immunity] should give way....

For more on the dispute about whether Jennings' conviction has indeed been properly expunged, see the discussion here, though the Ninth Circuit in that opinion didn't conclusively deal with Jennings' claim based on the December 2005 state court order.