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President Barack Obama announces his choice of White House Chief of Staff Jack Lew as the next Treasury Secretary in the East Room of the White House on January 10, 2013 in Washington, DC.
President Barack Obama nominated Jack Lew, his current chief of staff, to be the next Secretary of the Treasury Thursday, elevating his wonky former budget director to a position at the center of fights over the nation's deficit and spending.
"Jack knows that every number on a page, every dollar we budget, every decision we make, has to be an expression of who we wish to be as a nation, our values," the president said at the White House announcement of Lew's nomination.
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The president did not indicate who will replace Lew. The leading candidates for the next chief of staff are former Biden chief of staff Ron Klain and Deputy National Security Adviser Denis McDonough.
"I don't want to see him go, because it's working out really well for me to have him in the White House," Obama said of his departing chief. "But my loss will be the nation's gain."
Lew, known as a tough negotiator who clashed with House Republican aides during last year's debt ceiling negotiations, previously served as the director of the Office of Management and Budget under both Obama and former President Bill Clinton.
Lew will replace outgoing secretary Tim Geithner, who took the post at the start of Obama's first term, when financial markets were still roiling from the 2008 meltdown.
"I couldn't blame Tim when he told me he wasn't the right guy for the job," Obama joked.
Praising Geithner for his handling of the economy throughout his four year tenure, Obama noted that he pleaded with Geithner to stay on despite his onetime desire to leave before the end of Obama's first term.
Economist Greg Ip and CNBC's Steve Liesman share reactions from the markets, foreign capitals and Congress to Jack Lew as the Treasury Secretary nominee.
"When the history books are written, Tim Geithner's going to go down as one of our finest Secretaries of the Treasury," Obama said to sustained applause from the audience at the White House.
In remarks, Lew joked about his famously loopy signature, saying that he and Geithner share "a common challenge with penmanship." (The Treasury Secretary's signature appears on all paper currency.)
Obama wryly responded that, while he considered rescinding Lew's nomination over his sloppy signature, the new pick had promised to work to make at least one letter legible so as to "not debase our currency."
Critics have pointed out that Lew, who served as chief operating officer of Citigroup Alternative Investments in 2008 before coming to OMB, benefited from that unit's investments in anticipation of the housing market collapse.
That's likely to be discussed at his confirmation hearings, and Republicans like Senate Budget Committee ranking member Sen. Jeff Sessions have already voiced opposition to Lew's selection for the post.
On Thursday, Chamber of Commerce President Tom Donohue described the new Treasury pick as an experienced veteran of fiscal debates.
"Jack's been around for a long time," he said. "He's a tough dude."
For more about Lew's background, click here to read NBC's coverage from yesterday.
NBC's Bob Costantini contributed to this report.