Billionaire Paul Singer, one of the biggest donors in Republican Party circles, has decided to back Marco Rubio for president. Mr. Singer described Mr. Rubio as "the best explainer of conservatism in public life today, and one of the best communicators the modern Republican Party has seen. Marco Rubio can appeal to both the head and the heart." Wow!  Marco Rubio is the best explainer of conservatism!  Singer makes him sound like the Ted Cruz of the U.S. Senate! And what do we know about the endorser, Mr. Singer? Republican mega-bundler Paul Singer has quietly gotten involved in the fight for immigration reform, making a six-figure donation to a group involved in marshaling conservatives to support an overhaul of federal laws, POLITICO has learned. Singer has been involved for the past few months, officials said, beginning with the Forum's Bibles, Badges and Business network, one of its programs to corral support for immigration...(Read Full Post)