In this Saturday, Nov. 17, 2012 file photo, U.S. Sen. Marco Rubio, R-Fla., speaks during Iowa Gov. Terry Branstad's annual birthday fundraiser in Altoona, Iowa. Rubio and other prominent Republicans are calling for a sweeping review of how to prevent tragedies like the Newtown, Conn., massacre. For years, Republicans have adhered fiercely to their bedrock conservative principles, resisting Democratic calls for tax hikes, comprehensive immigration reform and gun control. Now, seven weeks after an electoral drubbing, some party leaders and rank-and-file alike are signaling a willingness to bend on all three issues.