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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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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This artist rendering shows Paul Clement (second from left) with Solicitor General Donald B. Verrilli Jr. (seated, right), addressing the Supreme Court on Wednesday. Justices pictured are (from left) Sonia Sotomayor, Stephen Breyer, Clarence Thomas, Antonin Scalia, Chief Justice John Roberts, Anthony Kennedy, Ruth Bader Ginsburg, Samuel Alito and Elena Kagan. Dana Verkouteren/AP hide caption

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As embattled, closeted lawyer Andrew Beckett, Tom Hanks brought gay rights to trial in 1993's Philadelphia. Bureau L.A. Collection / Corbis hide caption

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This artist rendering shows Roberta Kaplan, attorney for plaintiff Edith Windsor, addressing the Supreme Court during arguments on the Defense of Marriage Act on Wednesday. Dana Verkouteren/AP hide caption

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