Tom Udall of New Mexico, shown in a 2008 file photo, is leading the fight to change the rules on filibusters in the Senate. Ron Edmonds/AP hide caption

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Democratic Sen. Joe Manchin took a swipe last week at the president's leadership on budget talks, rankling fellow members of his party. The senator is shown sitting by himself last week in the House of Representatives as he awaited an address to a joint session of Congress by the Australian prime minister. Chip Somodevilla/Getty Images hide caption

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Massachusetts Institute of Technology professor Peter Diamond prepared to address the media last October after winning the 2010 Nobel Prize in Economic Sciences. Last week, more than a year after being nominated for a seat on the Fed, and facing Republican opposition, Diamond withdrew his nomination. Darren McCollester/Getty Images hide caption

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