Republican Billionaire Paul Singer Endorses Marco Rubio

What does an endorsement from a Republican billionaire mean? Absolutely nothing. Just ask Newt Gingrich who was endorsed by billionaire Sheldon Adelson in the Republican primary in 2012 and Mitt Romney who was endorsed by Adelson in the 2012 General. Altogether Sheldon Adelson spent a whopping $92 million supporting these 2 candidates in the 2012 Election cycle. Both of them came up short.  

Washington (CNN)—Paul Singer, a leading Republican fundraiser and donor, is endorsing Marco Rubio in his bid for the presidency.

The endorsement is a major boost for the Florida senator's campaign and is a setback for Jeb Bush, whose campaign has far outraised his rivals this year. The news comes days after Bush's much-criticized debate performance and could raise further concerns about his candidacy.

Singer is one of the GOP's leading bundlers, and is able to easily invest millions of dollars into a super PAC. He is likely to make a large contribution to one of the outside groups allied with Rubio's presidential campaign. And it could help Rubio's official campaign -- which only raised $6 million in the most recent fundraising quarter -- raise the cash necessary to challenge Bush.

In a letter to donors obtained by CNN, Singer, who backed Rubio during his Senate campaign in 2010, praised the senator's positions on higher education and welfare reform, his pledge to replace Obamacare and his support for Israel. Singer also called Rubio "the best explainer of conservatism in public life today" and the candidate best positioned to defeat Hillary Clinton next fall.