President Obama Monday named former Ohio Attorney General Richard Cordray to lead the government’s new consumer protection bureau, vowing to fight efforts to block the agency’s mission.

“We are going to stand up this bureau and make sure it is doing the right thing for middle-class families all over the country,” the president said mat Rose Garden ceremony at the White House.

The Consumer Financial Protecton bureau was a central feature of a law Congress passed last year to overhaul the financial sector. It will serve as a government watchdog over mortgages, credit cards and other lending when it starts operating this week.

Obama and his new appointee were joined by Elizabeth Warren, a special assistant to the president who is credited with standing up the agency. Consumer groups pushed for her to lead it. But Republican opposition effectively killed the nomination.

Obama called Warren “perhaps the leading voice in our country on behalf of consumers.”

Republicans already have threatened to block Cordray’s Senate confirmation as well.