WASHINGTON (Reuters) - Jeb Bush's move toward a 2016 presidential bid makes the path to the White House tougher for potential Republican rivals, including 2012 nominee Mitt Romney.
Multiple Romney donors said the former Massachusetts governor is less likely to run now that Bush has entered the fray, since they would compete for the same donors and supporters.
Bush, who announced Tuesday he was actively exploring a White House bid, has already spoken with several major fundraisers about his plans, said one top Romney donor.
The former Florida governor could also corner the support of high-profile donors in his home state, crowding out Florida Senator Marco Rubio, a rising Republican star.
"As far as the finance world goes, Jeb will be the 800-lb gorilla in the race, and Florida will be Jeb's," said Brian Ballard, a 2012 finance chairman for Romney.
Romney, who lost in 2012 to President Barack Obama, has told friends recently that he was open to jumping into the race depending on the shape of the Republican field.
"Mitt has said casually that if Jeb gets involved, that he perhaps would not get into the race," said Mel Sembler, a Romney backer in 2012 and a longtime Bush family donor in Florida.
A Romney insider said Bush's announcement does not change the former Massachusetts governor's plans.
New Jersey Governor Chris Christie and Representative Paul Ryan of Wisconsin are among the other potential White House contenders who could be affected by Bush's decision.
A Republican official said Christie could forgo a run to act as a kingmaker in the Republican contest. “This decision forces the guys in New jersey to speed up their timeline” for making a decision, the official said.
Donors said Rubio, who served in the Florida legislature while Bush was governor, would be particularly vulnerable.
"Hell yeah, there's only so much money in Florida," a long-time Republican fundraiser said. "It would make it very difficult for Rubio."
Rubio allies insisted his plans would not be affected.
"Marco's decision on whether to run for president or re-election will be based on where he can best achieve his agenda to restore the American dream - not on who else might be running," said Rubio spokesman Alex Conant.
Rubio plans to meet with donors in Miami in January but strategists were skeptical he could win them over.
"Logic, common sense tells me he will decide not to run," Sembler said.
Additional reporting by Steve Holland; Editing by John Whitesides and Lisa Shumaker