Senator John McCain began tapping into President Bush’s prized political donor base on Tuesday as his campaign announced that Mercer Reynolds, who helped Mr. Bush raise a record $273 million for the 2004 re-election campaign, would be the national finance co-chairman for Mr. McCain.
The development was a major sign that the Republican financial establishment was coalescing around Mr. McCain, who has often been at odds with his own party, particularly conservatives.
It also signaled that Mr. Bush’s political apparatus was moving into action for Mr. McCain, a onetime insurgent and competitor to Mr. Bush in 2000 who has had a difficult relationship with the president.
Mr. McCain’s advisers said that Mr. Reynolds, a wealthy Cincinnati executive and a former ambassador to Switzerland, would be of enormous help in reaching out to the president’s most valued contributors — the Bush campaign called them Rangers and Pioneers — on behalf of Mr. McCain.
“He knows them all, and hopefully we’ll get them on board,” said Charles Black, a senior adviser to Mr. McCain.
Advisers to both men said on Tuesday that the once-strained relationship between the president and Mr. McCain had improved and that Mr. Bush, who vouched for Mr. McCain as a “true conservative” in a television interview last weekend, would do whatever he was asked by his party’s nominee.
Mr. McCain is now the presumptive nominee, although he still faces a Republican competitor, Mike Huckabee, who continues to accumulate delegates despite Mr. McCain’s daunting lead.
Mr. Reynolds, who declined to be interviewed for this article, is of critical importance to the McCain campaign not simply because of his wealth but also for his layers of contacts with other wealthy donors.
Under campaign finance rules in large part created by Mr. McCain himself under the McCain-Feingold bill, individual contributions are limited to $2,300 per election cycle for both the nominating contests and the general election.
The result is that highly connected, prosperous people like Mr. Reynolds are of huge value to a campaign because they can call on many other highly connected, prosperous people to write checks, which is particularly vital to Republicans in a year when Democrats have far outpaced them in fund-raising.
In 2004, contributors to Mr. Bush who collected $100,000 in checks, otherwise known as bundlers, were called Pioneers. Those who collected $200,000 were called Rangers, after the Texas baseball team once partly owned by Mr. Bush.
Mr. McCain’s advisers said that the senator’s campaign would also be bestowing titles on its most prolific fund-raisers under an “incentive system,” with privileges for those who raised the most money.
Mr. McCain’s advisers said that the candidate, despite his signature legislative efforts to restrict the money spent on political campaigns, would not accept public financing and spending limits for this year’s general campaign.
But in 2007, Mr. McCain did agree to a nonaggression pact with Senator Barack Obama to accept public financing, about $85 million each for the general election, if the Democratic nominee did the same. Mr. Obama, who is raising money at a rate of $1 million a day, has since said he will not use public financing for the fall campaign.
Mr. McCain’s advisers insisted that the senator was not turning his back on a campaign finance system, which bans large “soft-money” donations to the political parties, that he helped put in place. “The senator’s always been an advocate of contributions from individual Americans,” said Wayne Berman, a major McCain fund-raiser. “It’s those contributions that are supporting his presidential campaign.”
Mr. Berman was one of numerous Bush supporters who signed up to raise money for Mr. McCain early last year, when the senator was in his first incarnation as the Republican front-runner. But the campaign fell far short of its $100 million fund-raising target and by last summer had nearly collapsed in debt and recriminations. In November Mr. McCain took out a $3 million loan to keep the race alive through New Hampshire. His primary victory there on Jan. 8 opened wallets all over the country. Since then he has held 20 fund-raisers and collected more than $12 million.
Other major fund-raisers for Mr. McCain include Henry R. Kravis, the financier; A. Gerald Perenchio, the former chairman and chief executive of Univision Communications, the nation’s largest Spanish-language broadcaster; and Lewis M. Eisenberg, the former finance chairman of the Republican National Committee and the former chairman of the Port Authority of New York and New Jersey.
This week and next Mr. McCain’s advisers are planning strategy meetings to set new money targets, set a fund-raising schedule and discuss how they might use Mr. Bush at fund-raising events. They are also working on hiring staff members and setting up “McCain for president” offices around the country.
“We have to talk about the short term and the long term,” Mr. Black said. “Basically you’re changing from a primary campaign that runs on fumes and volunteers to a national campaign.”