It looks like the Jeb Bush strategy — a strategy that seems to come from Right to Rise super PAC boss Mike Murphy — of attacking [mc_name name=’Sen. Marco Rubio (R-FL)’ chamber=’senate’ mcid=’R000595′ ] is really paying off.

Jeb Bush’s decision to attack old friend and new rival [mc_name name=’Sen. Marco Rubio (R-FL)’ chamber=’senate’ mcid=’R000595′ ] is backfiring, pushing important supporters to criticize the campaign’s tactics and driving one of Florida’s top fundraisers to officially quit and signal a shift in allegiance to the senator.

“I think the world of Jeb Bush. He was a great governor of Florida and is a really good person, but the campaign has hijacked his message,” said Brian Ballard, a Tallahassee lobbyist who contributed more than $25,000 of his own money and has raised hundreds of thousands of dollars more for Bush’s campaign and the super PAC supporting him.

So why is this a surprise to anyone? The Bush campaign has decided to attack Rubio because they see him as the most direct threat to Bush. Rubio appeals across demographic slices of the electorate, he polls very well with women, he isn’t saddled with the Bush name, etc. etc. This appeal has made him the most attractive conservative in the race to GOP establishment types. With Bush floundering, these establishment donors are looking for another horse. Bush’s only way to stay in the race is to lauch Charlie-Crist-researched attacks on Rubio, attacks that fell flat on their ass in Florida and will fall even flatter nationally.

One Republican who has worked for the Bush campaign said the staffers are taking Rubio’s bid for president personally, not professionally. Some have taken to calling Rubio “Judas,” a betrayer who should have deferred to the elder Republican, the source said, adding that the campaign’s upper echelon isn’t listening to the numerous voices in the conservative movement and the Republican Party who have become increasingly disillusioned with the negative tone.

“The campaign has been arrogant with donors, arrogant with staff, arrogant with Republicans and arrogant with the media,” the source said. “And now look at where we are: isolated.”

Worse yet for Bush, nearly all of the supporters who told POLITICO they are disappointed in his attack approach see Rubio as a viable alternative who would continue the tradition of conservative principles and policies that the former governor espoused when Rubio served simultaneously in the Florida Legislature. Already, they noted, Rubio is well ahead of Bush in national and state polls.

“For a substantial portion of the D.C. crowd — and I think this probably goes beyond D.C. — Marco is well liked,” said one major Bush donor and fundraiser from Washington. “I don’t know necessarily what is gained by picking fights with people.”

It it were just this one guy, one could portray it as a single disgruntled donor, which, by the way, is the way the Bush campaign is treating it. But the rot goes much deeper.

In the approaching days and weeks, the Rubio campaign will unfurl a “healthy” slate of additional congressional endorsements it secured after the Colorado debate, according to a source knowledgeable of its plans. What’s more, the campaign in the last week has locked down commitments from at least 25 previously undecided fundraising bundlers, who have already begun planning forthcoming events designed to harvest cash.

In the coming few weeks you are going to see Bush high-dollar donors and bundlers flowing to the Rubio campaign. Rubio looks like he can not only win the GOP primary but he looks like a general election winner, too. Bush looks more an more like what he is, a guy whose time has passed and whose heart really isn’t in this campaign.