President Obama tonight announced the most sweeping executive action on immigration in three decades, providing relief for an estimated 4.1 million undocumented parents of U.S. citizens and about 300,000 undocumented immigrants who came to the U.S. illegally as children.

“I know some of the critics of this action call it amnesty. Well, it’s not,” the president said from the East Room of the White House. “Amnesty is the immigration system we have today — millions of people who live here without paying their taxes or playing by the rules, while politicians use the issue to scare people and whip up votes at election time. “That’s the real amnesty — leaving this broken system the way it is,” Obama said. “What I’m describing is accountability.”

The action will be finalized Friday with the signing of a presidential memorandum at a rally in Las Vegas. It will fulfill, at least in part, the promise Obama first made in 2008 as a candidate to lift the threat of deportation from millions of people living in the U.S. illegally.