In one of his calls to action for Congress after the terrorist attack in San Bernardino, Calif., President Barack Obama urged lawmakers to pass legislation preventing suspected terrorists on the no-fly list from buying guns.

So far, Republicans have voted down this proposal, just as they have rejected other gun control measures.

While Obama and Democrats frame the act of denying weapons to potential terrorists as a no-brainer, Republicans argue that such legislation would unintentionally harm the Second Amendment rights of everyday Americans.

That’s because, Republicans say, not everyone on the no-fly list, which is a component of the FBI’s terrorist watch list, deserves to be on there—which is especially unfair, they say, because people belonging to such lists usually don’t know they are on them.