From left, Sen. Jeff Flake, R-Ariz., Sen. Chuck Schumer, D-NY, Sen. John McCain, R-Ariz., and Sen. Michael Bennett, D-Colo, arrive at a news conference after their tour of the Mexico border with the United States on Wednesday in Nogales, Ariz. The senators are part of the "Gang of Eight," a larger group of legislators collaborating on changes to immigration. Ross D. Franklin/AP hide caption

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The new rules' would reduce harmful emissions, the EPA says. David Paul Morris/Getty Images hide caption

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House Speaker John Boehner, R-Ohio, left, performs a mock swearing in for Rep. Don Young, R-Alaska, on Jan. 3, as the 113th Congress began. On Friday, Boehner condemned Young, the second most senior Republican in the House, for using the term "wetbacks," which Boehner called "offensive and beneath the dignity of the office he holds." Charles Dharapak/AP hide caption

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Same-sex wedding cake topper figurines at Cake and Art in 2008 in West Hollywood, Calif. David McNew/Getty Images hide caption

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Police stand guard in front of the U.S. Supreme Court on Wednesday as the justices hear arguments on the constitutionality of the federal Defense of Marriage Act. Jewel Samad/AFP/Getty Images hide caption

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Voters line up into the night outside a Miami polling station, some waiting for hours to vote in the 2012 presidential election. Wilfredo Lee/AP hide caption

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A woman views a Mitt Romney campaign ad in September, a month after the launch of an online government database that is supposed to make it easier for the public to see what political ads air in big markets, and how much is spent on them. Karen Bleier /AFP/Getty Images hide caption

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