President Joe Biden took executive action Thursday against a new type of firearm that both its proponents and critics say completely transforms the Second Amendment.

“Today, I’m announcing several initial steps my administration is taking to curb this epidemic of gun violence. Much more needs to be done,” the president said. “First, I want to rein in the proliferation of so-called ‘ghost guns.’ These are guns that are homemade, built from a kit, and include directions on how to finish a firearm.”