WASHINGTON – Hillary Rodham Clinton wants to make people gasp.

So do John Edwards, Barack Obama, Rudolph Giuliani, John McCain and Mitt Romney.

Each of the leading 2008 presidential candidates wants to raise so much money in the first full quarter of fundraising, which ends March 31, that he or she achieves what George W. Bush did in early 1999. His record-shattering $29 million first-quarter total drew audible gasps from reporters, drove several rivals out of the race and all but locked up the 2000 Republican nomination.

At the same time, the also-rans in this year’s early-money race want to avoid disappointing showings. That could drain their campaigns of energy, scare off new contributors fearful of backing losers and drive them to drop out.

“This first-quarter report will be the most important event to happen in the campaign cycle,” said Scott Reed, a veteran Republican strategist who ran Bob Dole’s 1996 presidential campaign. “Expectations are high for some of the candidates. And April could be the shakeout month for some of the campaigns and some of the campaign teams. Some lower-level candidates will face reality like Vilsack did.”

Weeks into his campaign for the Democratic nomination, former Iowa Gov. Tom Vilsack was driven out late last month by the cold shoulder he got from donors. “It is money and only money that is the reason we are leaving today,” he said.

Following the precedent that Bush set in 2000, which he and Democratic nominee John Kerry matched in 2004, most top candidates say they’ll pass up federal taxpayer funds for the primary campaign – and thus escape the legal limits on spending.

Several say they’ll also forgo federal money for the general election. That means that for the first time since the Watergate revisions of the 1970s, the fall 2008 campaign could see unlimited spending, most of it to pay for television advertising.

Insiders think the winner will need to raise and spend half a billion dollars: $100 million this year for the 40-day stretch of decisive caucuses and primaries in early 2008, $200 million for the period after the nominee is decided but before the late-summer party conventions and $200 million for the fall general-election campaign.

Candidates who want to compete thus must raise tens of millions – starting now.

Sen. McCain, R-Ariz., for example, is barnstorming the country all month to rake in cash, attending 17 fundraising breakfasts, lunches or dinners in Utah, Michigan, North Carolina, California, Pennsylvania, Washington, D.C., New Jersey, Texas and Virginia.

“We’re humping it, no question,” said Rick Davis, McCain’s campaign manager. “The fundraising you do now gives you options in the future.”

Reed guessed that each of the top three Republicans – Giuliani of New York, McCain and Romney of Massachusetts – could raise about $25 million this quarter. He also said that Romney, who raised $6.5 million in one day at a Boston event, could surprise people by leading the field in cash though he trailed in polls.

“A lot of people think he’s shaping up to be the John Connally of this cycle,” Reed said, a reference to the former Texas governor who led fundraising early in the 1980 campaign but won only one convention delegate against Ronald Reagan.

Among Democrats, Reed estimated that Clinton of New York and Obama of Illinois each could raise $25 million and Edwards could raise $15 million to $18 million. “He’s the tortoise in the race,” Reed said.

The winner of the race will be clear at the end – with the nomination and election. But scoring this first lap is a more subjective game, in which the news media declare people winners or losers based on how well they do compared with expectations.

Clinton, for example, says she hopes to raise $15 million. Aides said she set that figure because it was twice what Edwards raised in his first full quarter in the 2004 campaign, when he led the field. But he was an unknown senator from a midsize Southern state, not the best-known woman in American politics with ready access to the moneyed elites of New York and Hollywood.

A more apt comparison is Bush’s first three-month haul of $29 million. And that was when each contribution was limited to $1,000. Clinton can get a $2,300 check from each contributor this time and thus raise money twice as fast as Bush did.

By claiming that her goal is less than half what Bush raised, she could be trying to lower expectations while easily raising more – and generating that gasp.

Clinton plans several big-buck galas in coming weeks. Her husband will make his campaign debut by starring at two dinners, one March 18 in New York and one in Washington two days later. Hollywood friends will host a star-studded dinner at the Beverly Hills home of supermarket magnate Ron Burkle on March 24.