As John Kerry (search) eliminates his Democratic presidential rivals one by one, he may soon run up against his promise to spend no more than $45 million until the party's nomination is decided.

To keep his pledge, it is in Kerry's interest to nudge challengers John Edwards (search) and Howard Dean (search) from the race as soon as possible. An easy victory in Wisconsin's primary Tuesday might help. Kerry spokesman Michael Meehan (search) said it is hard to say when the Massachusetts senator will consider himself the presumptive nominee.

"The news media generally makes that ruling," Meehan said.

To keep his pledge, it is in Kerry's interest to nudge challengers John Edwards and Howard Dean from the race as soon as possible. An easy victory in Wisconsin's primary Tuesday might help. Kerry spokesman Michael Meehan said it is hard to say when the Massachusetts senator will consider himself the presumptive nominee.

"The news media generally makes that ruling," Meehan said.

Kerry imposed the spending cap on himself in November, when he announced he would follow the leads of President Bush and Dean and skip public financing for the primaries.

Kerry said he would abandon the public financing program's state-by-state spending caps, which freed him to use more cash in early-voting states such as Iowa and New Hampshire.

At the same time, he accepted the challenge from campaign finance watchdogs to stick to the program's overall $45 million limit "until the nomination is decided."

Kerry challenged Dean to do the same. Dean, the first Democrat to opt out of the post-Watergate public financing system, did not take the bait.

As the early front-runner, Dean raised a party record $41 million last year, nearly twice as much as Kerry. The former Vermont governor had spent nearly all of it by Dec. 31.

"Our point was there's no clear cutoff date for when there's a nominee until the August convention," Dean spokesman Jay Carson said. "So it didn't make a whole lot of sense to us, still doesn't make a whole lot of sense to us, to unilaterally disarm" when Bush has millions to spend whenever he chooses to do so.

For candidate who accept public financing, the $45 million limit applies until the convention in late summer.

Since their decisions last fall to forgo government funds to help finance their campaigns, the political fortunes of Dean and Kerry have switched. Dean still has raised more overall than Kerry, but the fund-raising momentum is with Kerry after his primary victories.

Kerry has raised at least $7 million this year, compared with at least $5 million for Dean and at least $3 million for Edwards. Several hopefuls, including Wesley Clark, Dick Gephardt and Joe Lieberman, left the race this year.

Bush has raised at least $15.8 million since Jan. 1, boosting his re-election total to about $150 million.

Democratic strategist Tony Coelho said Kerry's biggest fund-raising problem will come after he clinches the delegates he needs to become the presumptive nominee.

Coelho said a big victory in Wisconsin would be enough to win Kerry an unofficial coronation by the media and public, and a flood of Democratic money would follow.

If that happens, it would come just in time, given Kerry's self-imposed cap and the millions Bush is poised to spend, Coelho said.

He believes Kerry could break at least the $100 million mark in fund raising, aided by contributions from other candidates' donors, including some of Dean's record-setting Internet supporters.

"I would say after Tuesday, the cap is off," said Coelho, chairman of Democrat Al Gore's 2000 presidential campaign.

Late last year, Kerry said he would loan his campaign more than $6 million to keep it afloat. He started 2004 with little campaign cash left. Spokesman Meehan would not say how much the candidate has spent this year.

Kerry began January having spent about $27 million, leaving him $18 million under his limit.

If his expenses for salaries and other overhead are comparable to December's and estimates of his advertising spending hold true, Kerry will have spent about $9 million to $10 million so far this year.

That would leave him with around $8 million to $9 million before he reached his $45 million spending cap, which could burn up quickly if several candidates continue to stay in the race.

Two weeks after Wisconsin's primary, voters in 10 states, including California, New York and Ohio, hold contests.