Making good on a State-of-the-Union promise, President Obama raised the minimum wage to $10.10 an hour for federal contractors today.

The hike won't take effect until Jan. 1 of next year, but Obama did so through an executive order, circumventing Congress. He signed it in the East Room, flanked by contract workers.

"While Congress decides what it's going to do - and I hope this year, and I'm going to work this year, and urge this year that they actually pass a law - today I'm going to do what I can to help raise working Americans' wages," Obama said, to applause, during brief remarks before signing the order.

In his State of the Union speech, Obama promised today's executive order and called on Congress to raise the national minimum wage. He repeated that call today.

"Every American deserves to know where your elected representative stands on this issue. So ask your senator, ask your representative in the House: Do you support raising the federal minimum wage to $10.10 an hour? If they say yes, tell them 'good job.' You know, they don't hear that that often," Obama joked. "So give them a pat on the back, give them a hug and let them know, way to go. That's the right thing to do. If they say no, you know, be polite - I mean, don't just yell at them - but say, Well, why not? Ask them to reconsider siding with an overwhelming majority of Americans."

The new minimum wage will apply to people working on new federal contracts agreed to after Jan. 1, 2015.

The White House has claimed that the move will benefit "hundreds of thousands" of employees, but the methodology of its estimate has gone unexplained. Pressed by ABC's Jon Karl during today's press briefing, Labor Secretary Thomas Perez said that estimate applies to 3-5 years of contract work, after the new policy takes effect. He would not elaborate on how many hundreds of thousands of workers the move will affect.