BOSTON — Trailing two better-known rivals in the polls, Republican presidential contender Mitt Romney is trying to prove his political viability using a different yardstick — cash in the campaign account.

The former Massachusetts governor had scheduled 20 fund-raising events this month, all in advance of an end-of-the-month deadline that will give the first true look at the fund-raising prowess of all the 2008 presidential contenders.

Reports detailing how much money was raised by March 31, as well as how it was spent, will become public by April 15.

The first total is especially important for Romney, who has been trying to elevate his name recognition nationally after placing a distant third behind former New York mayor Rudy Giuliani and Sen. John McCain, R-Ariz., in several national polls gauging the GOP candidates.

"What he's trying to do is establish himself as a leading candidate by being able to compete financially with Giuliani and McCain," said Anthony Corrado, a government professor at Colby College who specializes in presidential campaign finance.

"If he were to beat one of those guys, that would be a news story."

In an Associated Press-Ipsos poll conducted earlier this month, Giuliani led among Republican voters with 35 percent support, followed by McCain, 22 percent; former House Speaker Newt Gingrich, 11 percent; and Romney, 8 percent. Gingrich has said he'll decide later this year whether he'll become a candidate.

During the 2004 campaign, then-Sen. John Edwards, D-N.C., saw his national profile skyrocket after raising $7.4 million during the first quarter of 2003 — about $100,000 less than Sen. John Kerry, D-Mass., the eventual Democratic nominee. Kerry ended up tapping Edwards to be his running mate.

Similarly, former Vermont Gov. Howard Dean raised $7.5 million in the second quarter of 2003, making him a household name and propelling him to record Internet fund-raising totals later in the year, including $14.8 million raised in the third quarter.

This cycle, some campaigns are setting $15 million to $20 million as a first-quarter target. Political analysts estimate 2008 candidates will have to raise $100 million each this year to be competitive in next year's presidential primaries and caucuses.

Romney got a decent start by raising $6.5 million during his first event, an innovative "National Call Day" in which he brought his top supporters to Boston on Jan. 9 and had them seek donations within their professional and personal networks. He also raised about $1.4 million over the Internet during the first month of the campaign.

Corrado believes that at that pace, Romney could surprise his rivals by raising over $15 million before the end of March.

"Clearly the inside-the-Beltway folks, the opinion leaders, are looking at that as a leading indicator of popular support and an ability to mount a national campaign," Romney spokesman Kevin Madden said of whatever first-quarter total is achieved.