From yesterday's Third Circuit en banc opinion in Williams v. Attorney General, written by Judge Paul Matey (and citing, among others, our own Will Baude):
The Second Amendment is a primary protection against tyranny, a strong bulwark securing American liberty, and an indispensable means of defending the public good. So courts testing restrictions on these "most sacred" and "necessary" rights must consider the history and tradition of firearm regulations with care and rigor. Edward Williams had two convictions for driving under the influence of alcohol in the early 2000s, the second of which (unbeknownst to him) triggered 18 U.S.C. § 922(g)(1), which purports to make it "unlawful" for persons convicted of "a crime punishable by imprisonment for a term exceeding one year" to possess firearms. Seeking to restore his rights, Williams filed for a declaratory judgment to confirm that § 922(g)(1), as applied to him, runs afoul of the Second Amendment.
The court ruled in Williams' favor; here are some excerpts from the long opinion:
We start [the Second Amendment inquiry] by asking the regulator whether its proposed liberty definition (or restriction, though every definition has some contracting element) is consistent with tradition. In assessing the response, we look for a custom of similar definitions.
A definition fitting within common and longstanding firearm regulation helps the regulator because long acceptance evidences noninfringement of the right. In contrast, it is likely impossible to show equivalence when the challenged restriction applies to people, places, and things that have gone unregulated for most of America's existence. Time is essential, and a recent innovation must be weighed against our "Anglo-American common-law tradition." An enduring custom since the founding is all but dispositive—one would be hard-pressed to argue that a state can prohibit the purchase of a flintlock musket. The same framework applies with respect to permissible regulations of people: if a regulation was common throughout our history, that is strong evidence that it does not infringe the right.
That is not the case here given the novelty of forever restricting all felons from possessing firearms for lawful purposes. The Federal Firearms Act of 1938 first made it "unlawful" for "any person who has been convicted of a crime of violence or is a fugutive [sic] from justice" to possess a firearm. {A "crime of violence" was defined in the Act to mean "murder, manslaughter, rape, mayhem, kidnaping, burglary, housebreaking; assault with intent to kill, commit rape, or rob; assault with a dangerous weapon, or assault with intent to commit any offense punishable by imprisonment for more than one year."}
In 1961, Congress expanded this prohibition, abandoning a focus on violence in favor of a technical bar on any person convicted of a "crime punishable by imprisonment for a term exceeding one year." By this point, "a crime punishable by imprisonment for more than one year" was the common approximation for "felony." The late entrance of a regulation tying felonies to gun possession disproves any longstanding customary contraction of the liberty codified in the Second Amendment.

