Members of the anti-war activist group CodePink interrupt a Senate Armed Services Committee hearing with Defense Secretary Chuck Hagel (left) and Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff. J. Scott Applewhite/AP hide caption

itoggle caption J. Scott Applewhite/AP

GOP Sen. John McCain greets well-wishers as he arrives to visit a pro-European Union rally in Independence Square in Kiev, Ukraine, on Dec. 15. Strong criticism and trips like this landed the Arizona senator on Russia's travel blacklist. Sergei Chuzavkov/ASSOCIATED PRESS hide caption

itoggle caption Sergei Chuzavkov/ASSOCIATED PRESS

Some Republican lawmakers hope President Obama sends arms to Syria's rebels — and cruise missiles after Syrian military targets. Jonathan Sunderman/AP hide caption

itoggle caption Jonathan Sunderman/AP

In this photo provided by Mouaz Moustafa and the Syrian Emergency Task Force, Sen. John McCain, accompanied by Moustafa (right) visits rebels in Syria on Monday. McCain, who slipped into the country for a surprise visit, favors providing arms to rebel forces in Syria. Mouaz Moustafa/AP hide caption

itoggle caption Mouaz Moustafa/AP

Sen. John McCain, right, as he endorsed Mitt Romney's bid for the presidency earlier this month. Chip Somodevilla/Getty Images hide caption

itoggle caption Chip Somodevilla/Getty Images