Sen. Mary Landrieu, D-La., speaks at an Oct. 2013 news conference on Capitol Hill in Washington. Landrieu's support for the Affordable Care Act is center stage in her campaign for a fourth Senate term. Evan Vucci/AP hide caption

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The Capitol Dome is visible through the skylights of the new Capitol Visitor Center. Susan Walsh/AP hide caption

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President Obama speaks in the James Brady Press Briefing Room of the White House in November 2013, shortly after the Senate voted 52-48 to weaken the power of the filibuster. Evan Vucci/AP hide caption

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Levees, like this one in New Orleans, must be certified by the U.S. Army Corps of Engineers before appearing on federal flood maps. This change has resulted in higher flood insurance premiums in some areas. Mario Tama/Getty Images hide caption

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Sen. Mary Landrieu, D-La., has won some conservative supporters in her state, but her support for Obamacare is putting her re-election at risk. Evan Vucci/AP hide caption

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