Democrat Barack Obama raised $22 million in May for his presidential campaign, his weakest fundraising month this year, and ended the month with $43 million cash on hand, the campaign reported Friday.

Though Obama has been the fundraising leader in the presidential contest, his May totals are just slightly above Republican rival John McCain's fundraising for the month. Overall, Obama has raised more than $287 million during the past 17 months, while McCain has raised a total of $115 million.

Obama, who is bypassing the public financing system in the general election, reported that nearly $10 million of his cash on hand was exclusively for the general election.

McCain and Obama have almost equal amounts in the bank to spend during the months between now and their party conventions in late summer _ a level of parity between the two candidates that would have been unfathomable just a few months ago.

Obama reported spending $26.6 million in May, a month where he moved to end his Democratic contest with Sen. Hillary Rodham Clinton. Obama and Clinton traded primary victories during the month but Obama continued to build his delegate advantage. He secured the nomination June 3, winning that day's Montana primary but losing to Clinton in South Dakota. Clinton ended her campaign June 7.

The candidates had until midnight Friday to file their May fundraising reports with the Federal Election Commission. McCain filed his Thursday and the Obama campaign released top figures from their report Friday evening, before filing their document with the FEC. Clinton had yet to file her report.

The May figures place Obama and McCain on nearly equal footing. McCain raised $21 million in May and reported $31.6 million cash on hand at month's end.

But McCain also benefited from the Republican National Committee, which reported $53.5 million cash on hand to the Democratic national committee's $4 million. The parties are already working with their respective presidential candidates to coordinate their campaigns.

Obama announced Thursday that he would become the first major party candidate to bypass public financing in the general election. McCain said he would participate in the system, which will limit him to spending no more than $85 million from September until Election Day in November.

Obama's decision gives greater significance to his efforts to capitalize on Clinton's support for the general election. Her donors would be a rich vein to tap.

First, however, Clinton needs substantial help retiring her debt, now more than $20 million. Many of her loyal donors have already contributed the maximum to her campaign, so she needs some new sources of money. That's where Obama comes in _ his donors help her out, her donors help him.

"It's far more productive for Obama to have Hillary 100 percent focused and engaged on campaigning and raising money for him in the fall rather than having to do fundraisers at the same time to retire her debt," said Hassan Nemazee, a Clinton national finance chairman.

"It would clearly make life easier for those of us in the Clinton world who would like to help Senator Obama raise the types of moneys that are necessary from the Clinton world to be in a position to point out, 'Look what Senator Obama has done for Senator Clinton.'"

Clinton and Obama will meet with her top fundraisers next Thursday in Washington, then both will campaign together Friday.

Some Obama backers point out that Obama's vaunted Internet fundraising relied on major events to motivate small donors. Obama's contributions tended to spike especially around primary elections. But the primaries are now over, summer vacations are ahead and donors may not be as driven to give between now and the Democratic National Convention in late August.

But Steve Weissman, associate director at the Campaign Finance Institute, pointed out that Democrat John Kerry in 2004 was able to raise $185 million between March, when he secured the nomination, and August, when the party held its convention.

"People are mobilized," Weissman said. "This is the election."

Obama said he is expecting McCain to have significant help from the Republican Party and from outside groups.

So far, though, few conservative outside groups have stepped into the presidential election and those that have have spent little money. In a news conference Friday, Obama defended his decision to go outside the public financing system.

"There are a lot of outside groups that are potentially going to be going after us hard," he said. He also pointed out that McCain advisers have made a point of featuring the RNC's financial advantage.

"So you know, this isn't speculative on my part," he said. "I think it's something that we've seen in the past and it's something that we continue to be concerned about."