It didn’t happen on the debate stage or at the ballot box,but Marco Rubio won a major victory Friday night by securing thesupport of a major Republican donor.

Paul Singer, a hedge fund manager who has amassed a fortune ofabout $2 billion, has thrown his support behind Rubio, reported TheNew York Times. As of Friday, Singer had not committed himself yetin the GOP field.

“[Rubio is] the best explainer of conservatism in publiclife today, and one of the best communicators themodern Republican Party has seen,” Singer wrote ina letter to other potential donors. “Marco Rubio can appealto both the head and the heart.”

The move will likely yield Rubio millions of dollars for acampaign that until now has distinguished itself as ashoestring, low-cost operation. Singer is also a major bundler forother donors, and sent some of them aletter Friday, arguing Rubio is the candidatein the best position to defeat likely Democratic nominee HillaryClinton.

Singer was one of the first major GOP donors to back Rubio inhis upstart primary challenge against Charlie Crist forFlorida’s Senate seat in 2010.

Rubio may have gained his new donor thanksto his strong showing in Wednesday night’sRepublican primary debate. After relatively low-key performances inthe first two GOP showdowns, Rubio acquitted himself well whenchallenged by the moderators on his personal spendingand by Jeb Bush regarding his missed Senate votes. Theperformance was a likely tipping point for Singer, whojust days ago remained skeptical of Rubio’s campaignstrategy.

Singer’s doubts seemed to have vanished. Singerlauds Rubio as a serious thinker on foreign policy andan “informed and assertive decision-maker” in hisletter to Republican donors.

His endorsement is all the more important because it denies thatsame endorsement to several other Republicans. Jeb Bushand Chris Christie were both jockeying for his support.

Now, Bush has suffered yet another tough blow to a campaign thathas struggled with staff cutbacks, slowed fundraising, and drops inthe polls. For a candidate who chief asset was his strongfundraising and aura of inevitability, this latest development mayjust prove lethal. Christie, meanwhile, has missed another bigdonor who could have helped kickstart a campaign that has struggledto get off the ground.

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