From the Wizard Nate Silver's column:
Until recently, Senator Marco Rubio of Florida had occupied something of a sweet spot in Republican politics: a favorite of the Tea Party but also trusted by the establishment wing of the G.O.P.http://fivethirtyeight.blogs.nytimes...ight&seid=auto
Mr. Rubio’s embrace of comprehensive immigration reform, however, appears to have upset that delicate balance, and his support has slipped among the Republican base. The mention of his name drew boos at an anti-immigration reform Tea Party rally on Capitol Hill in mid-June, and recent public opinion surveys, taken amid the debate on immigration legislation, found his favorability rating falling and his standing in 2016 Republican primary matchups eroding.