Via CNN:

Sen. Orrin Hatch, Republican of Utah: "I'm glad the President finally laid out his position to the American people, but changing the definition of marriage is not something I can support. The sanctity of marriage is not to be taken lightly. Sanctioned by God, this sacred union between a man and a woman must be respected, preserved, and fostered as the foundation for healthy and prosperous families and communities."

Sen. Chuck Grassley, Republican of Iowa: "I support traditional marriage. I voted for the Defense of Marriage Act, which was signed into law by President Clinton. It defines marriage as a union between one man and one woman and prevents states from being forced to honor the decisions of other state courts. I also voted twice in 2006, in the Judiciary Committee and on the Senate floor, for a joint resolution that would have amended the federal Constitution to define marriage as between one man and one woman. The President's announcement today and his flip-flopping on the issue aren't surprising given the White House being entirely focused on political advantage for the November election right now and the demands of the President's political base and supporters. However, the majority of voters in every state who've had a chance to have their say with a referendum on same-sex marriage have voted against it. In Iowa, voters responded to the state Supreme Court decision in favor of same-sex marriage by ousting the justices. There also doesn't seem to be support for the President's position in the Senate since the Democratic majority hasn't brought up the issue for a vote, and you have to assume the leaders would if the votes were there."

Sen. Marco Rubio, Republican of Florida, asked by CNN Congressional Correspondent Kate Bolduan for his reaction: "I thought he already did. That's what Joe Biden said. So he now agrees with his vice president." Asked "So, what's your reaction?" Rubio said: "I've disagreed with him on that position. I agreed with the old Barack Obama."