“The gun lobby may be holding Congress hostage, but they can’t hold America hostage,” the president said.

The White House released details of the plan on Monday, after Obama met with attorney general Loretta Lynch. The executive action will require all gun dealers to be licensed, including those who sell online and at gun shows, thus clamping down on dealers who pass themselves off as “hobbyists” or “collectors.” It closes a loophole that allows people to acquire guns through “gun trusts” without background checks, and increases the responsibility of gun dealers for reporting missing guns. It includes a plan to hire more staff to process background checks and enforce gun laws, and allocates $500 million to mental-health care.

“Everybody should abide by the same rules,” Obama said in his address. He outlined the steps of his plan, which also included improving gun safety technology. ”If a child can’t open a bottle of aspirin, they shouldn’t be able to pull a trigger on a gun,” he said.

Republicans have already threatened to throw obstacles at Obama’s executive order. A powerful House Republican, John Culberson, sent a letter to Lynch threatening to cut funding to the Department of Justice if it enforces the order. Republican presidential candidates, meanwhile, vowed to undo Obama’s plans if they won the White House in next year’s race. “I will veto. I will unsign that so fast,” said frontrunner Donald Trump.

Executive action is a limited tool of power. It allows the president to, for instance, give more resources to a government agency, but he would not have been able to push through a comprehensive gun control law acting solely by himself. Eric Posner, a law professor and expert on executive action told Bloomberg that Obama “has to interpret [the Second Amendment and Supreme Court rulings] in a reasonable way…He can’t just make up any interpretation.”

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