Rep. Michele Bachmann (R-Minn.) raised more than $2 million in political contributions over the first 90 days of 2011, she reported Friday — a sum that serves as a reminder of her fundraising prowess as the 2012 Republican presidential campaign enters a crucial early stage.

The Minnesota conservative raised $1.7 million for her congressional reelection fund and an additional $500,000 for her federal political action committee.

Her donation total slightly exceeds the $1.8 million former Massachusetts governor Mitt Romney announced Thursday that he brought in via his Free and Strong America PAC in the first quarter. Candidates can transfer money from their personal campaign committee to a presidential account but not from a political action committee.

Bachmann’s strong first quarter showing comes on the heels of her raising $13.5 million for her 2010 campaign, by far the largest total compiled by any House challenger or incumbent for a single election.

The impressive first-quarter numbers give Bachmann and Romney a bit of a tailwind heading into the most crucial three-month period for presidential contenders to establish their financial bona fides.

Money has not always proven determinative in past contests. For example, Romney far outspent Sen. John McCain (R-Ariz.) in the 2008 primary campaign but ultimately lost the nomination.

But anyone who is serious about the 2012 GOP nomination needs to prove between now and June 30 — the second quarter’s end — that Republican donors are investing in them. And fundraising might matter more than usual in this Republican presidential fight for two reasons.

First, President Obama is setting himself up to be the greatest fundraising force in U.S. politics. After collecting $750 million in the 2008 campaign, Obama campaign manager Jim Messina has created a program for 400 major donors to each collect $350,000 by the end of 2011.

That adds up to $140 million in 2011 alone if all donors make their number. If 300 make the target — a more likely possibility — that’s still $105 million raised for the Obama reelection effort before a single vote has been cast on the Republican side.

Although no Republican — not even Romney — will likely equal Obama in fundraising, any GOP candidate must prove an ability to collect some threshold amount of money over the next three months to prove that he (or she) would be financially viable against Obama.

Second, the Republican field is as undefined and, therefore, unpredictable as any in modern memory. Romney is the nominal front-runner, but he has the narrowest of edges against a crowded pack.

That lack of a clear front-runner means that the 2012 Republican race is likely to be a momentum-driven contest. The first indicator of momentum in any race, but especially a presidential contest, is money.

Donors are, after all, investors, and convincing them to buy in at the ground level is an early sign of building momentum. (Remember that Howard Dean’s out-of-nowhere candidacy first jumped onto the national radar screen when he raised $7.6 million in the second quarter of 2003.)

The more a candidate raises early on, the more of a winner he or she looks like.

It’s hard then to overstate the importance of the next 90 days, especially for everyone not named Romney, Palin, Gingrich or Huckabee. Those four have enough name identification to start their bids later in the year, although each has to worry about a candidate outside of the quartet using the second quarter to springboard past him or her.

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