President Obama revealed a sweeping immigration overhaul Thursday, announcing plans for programs that will serve to protect around 5 million unauthorized immigrants from immediate deportation.

In the speech, Obama named several new policies he said he had the authority to make unilaterally—including a new legal status that would defer deportation of the parents of U.S. citizens.

"If you've been in America for more than five years; if you have children who are American citizens or legal residents; if you register, pass a criminal background check, and you're willing to pay your fair share of taxes - you'll be able to apply to stay in this country temporarily, without fear of deportation," Obama said from the White House. "You can come out of the shadows and get right with the law."

The action will also enable more foreign-born students to qualify for the DREAM program and extend visas for graduates of American universities with "high-tech skills."

The executive actions will be difficult for Republicans to block, the New York Times reports:

Even as Republican lawyers analyzed what the White House said was the legal basis of Mr. Obama's actions, it remained unclear how they might undo them. The agency that will carry out most of the president's executive actions, Citizenship and Immigration Services, is funded with application fees, and does not rely on a budget vote in Congress to keep operating.

The president said he'll repeal the actions just as soon as Congress gets around to passing its own immigration legislation.

"The actions I'm taking are not only lawful, they're the kinds of actions taken by every single Republican President and every single Democratic President for the past half century," Obama said. "And to those Members of Congress who question my authority to make our immigration system work better, or question the wisdom of me acting where Congress has failed, I have one answer: Pass a bill."