Presumed Republican nominee Mitt Romney and his party raised a sizable $40 million last month from donors who want him to replace President Obama, but most of the people who supported his primary election challengers have not yet come to his aid.
An Associated Press review of campaign finance data found that only a few hundred donors who contributed to such primary rivals as Newt Gingrich or Rick Santorum have changed course and gave to Mr. Romney's campaign or the Republican Party in April. That has happened even as Republican stalwarts and some former rivals have called on supporters to rally around Mr. Romney's White House run.
Mr. Romney is hardly hurting for cash, having reported more than $61 million in the bank by the end of April. But financial reports released Sunday reveal a potential struggle for Mr. Romney in persuading his party's more conservative donors to open their wallets for him, although there are still more than five months until Election Day.
Out of more than 50,000 donors who gave to other candidates such as Mr. Gingrich, Mr. Santorum and Texas Gov. Rick Perry since the start of the nomination race, fewer than 600 appeared to write checks to Mr. Romney in April, the AP's review of Federal Election Commission reports found. Roughly the same number contributed to the Republican National Committee, which is now helping Mr. Romney's campaign.
A Romney spokeswoman did not immediately respond to requests seeking comment late Sunday.
Mr. Romney has been aggressively courting conservatives, speaking out recently against China's "one-child policy" and addressing graduates at the evangelical Liberty University. Last month, Mr. Romney told Breitbart News that the mainstream media were involved in a "vast left-wing conspiracy to work together to put out their message and to attack me."
Wealthy donors like former Santorum supporter Foster Friess are now supporting Mr. Romney, realizing that his sizable delegate count and financial strength all but guarantee his nomination this summer. Other eventual Romney donors had already given early to his rivals, partly to support a spirited debate during the primary season.
Willis J. Johnson, founder of auto dealer Copart USA, contributed to Mr. Perry and Mr. Gingrich last year because he personally liked Mr. Perry and admired Mr. Gingrich's insistence on quizzing Mr. Romney during debates. "I think this administration is trying to take money away from small businesses" in part by raising taxes, Mr. Johnson said.
Other conservatives, however, have been warier. One blog post last week on the conservative RedState.com, referring to Mr. Romney's Liberty speech, asked: "Mr. Romney said that marriage is between one man and one woman. He got deafening applause. But where was he when it mattered?"
About a quarter of Romney April-turnaround donors gave checks of $2,500 or more, including amounts up to the maximum $30,800 legally allowed to a political party. In March - just before Mr. Romney started raising general election cash - about 300 former Santorum and Gingrich supporters contributed to the former Massachusetts governor's campaign.
Mr. Santorum dropped out of the race in April and Mr. Gingrich in May, even though Romney's momentum was growing before then. A report detailing the contributions of Mr. Romney's joint-fundraising committee is expected this summer.
April's financial reports were expected to be at the FEC by midnight Sunday.