An American flag flies at half-staff outside the U.S. Supreme Court after the death of Justice Antonin Scalia. The fight to replace him could be historic, resulting in the longest vacancy in history. Brendan Smialowski/AFP/Getty Images hide caption

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President Obama has reason to smile. He's now just three votes shy of being able to sustain a veto of a resolution of congressional disapproval of his Iran nuclear deal — that is, of being able to advance the deal over Republican objections. Saul Loeb/AFP/Getty Images hide caption

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Sen. Ted Cruz prays before the start of his Religious Liberty Rally last weekend in Des Moines, Iowa. The event was part of Cruz's push to energize evangelical voters. Scott Olson/Getty Images hide caption

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Ted Cruz Rallies Evangelicals In Campaign To Defund Planned Parenthood
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Rep. Ed Perlmutter shakes hands with Carlyn Meyer and other members of the groups J-Street and MoveOn.org as they urge him to support the Iran nuclear deal at an event in Denver. J-Street plans to spend about $5 million on ads in this fight, which is vastly dwarfed by the $20 million to $40 million from groups like AIPAC that oppose the agreement. Jason Bahr/Getty Images hide caption

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Lobbyists Spending Millions To Sway The Undecided On Iran Deal
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Marine Corps Commandant Gen. Joseph Dunford Jr. testifies Thursday during his Senate Armed Services Committee confirmation hearing to become the chairman of the Joint Chiefs of Staff. Cliff Owen/AP hide caption

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Senate Foreign Relations Committee Chairman Sen. Bob Corker, R-Tenn., center, and the committee's ranking member Sen. Ben Cardin, D-Md., right, were all smiles April 14 after the committee passed an agreement on oversight of Iran negotiations. But the bill has run into some outspoken opponents in the full Senate. Andrew Harnik/AP hide caption

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Full Senate Debates May Reveal Recent Bipartisanship As An Illusion
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Senate Minority Leader Harry Reid, D-Nev., (left) and Majority Leader Mitch McConnell, R-Ky., at a ceremony last month at the U.S. Capitol. Chip Somodevilla/Getty Images hide caption

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Has The Senate Found It's More Fun To Be Functional?
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Vice President Biden and House Speaker John Boehner wait for President Obama's State of the Union address in front of a joint session of Congress in 2012. As vice president, Biden is also leader of the U.S. Senate, but only gets a vote when senators are evenly divided. Saul Loeb/AP hide caption

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Former Massachusetts Sen. Edward William Brooke speaks in the Rotunda on Capitol Hill in Washington, in 2009 during a ceremony where he received the Congressional Gold Medal. Brooke died on Saturday at age 95. Alex Brandon/AP hide caption

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Senate May Need Every Minute To Meet Government Funding Deadline
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Republican U.S. Senate candidate Dan Sullivan greets supporters on election night in Anchorage. The as-yet-undecided race between Sullivan and Democratic incumbent Sen. Mark Begich was the hottest in the state. Ted S. Warren/AP hide caption

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Colorado Republican Rep. Cory Gardner officially announces his candidacy for the U.S. Senate at Denver Lumber Co. on March 1. Gardner will run against Democratic incumbent Mark Udall. Chris Schneider/AP hide caption

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