Obama could take the less risky path on guns by directing the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) to redefine its guidance on who is considered a dealer under federal gun law. This would be advisory and lack the force of law, which would mean that prosecutors could not rely on it when pursuing small gun dealers.

“The guidance could be used as evidence that prosecutors made a reasonable interpretation that a dealer needed a license, but it’s not binding,” said James Jacobs, law professor at New York University and author of the 2004 book “Can Gun Control Work?”

“In a way, it’s more like a speech, like the head of the ATF saying who needs a federal dealer’s license,” he said.

Obama could choose an even more cautious route and direct the ATF to begin the formal administrative rulemaking process to change its regulations for who is considered a firearms dealer under the existing Gun Control Act. Agency action that includes the chance for public comment would create an enforceable rule that would likely pass legal muster, but that process probably would not conclude before Obama leaves office in January 2017.