In fundraising, former Massachusetts Gov. Mitt Romney this quarter likely surpassed all his rivals for the GOP presidential nomination. His campaign today announced it raised $18.25 million in the past three months, more than half of which was garnered through a one-day phone bank fundraiser held in Las Vegas on May 16.

That places Romney ahead of any of the other GOP contenders who have so far reported their fundraising totals for the second quarter. The next closest — Rep. Ron Paul (R-Tex.) — posted an unimpressive $4.5 million. Former Minnesota Gov. Tim Pawlenty reported an anemic $4.2 million, former Utah Gov. Jon Huntsman a meager $4.1 million (half of which was his own money), former Godfather’s Pizza CEO Herman Cain a tiny $2.46 million and former House Speaker Newt Gingrich, already deep in debt, just $2 million. But not everyone running has revealed fundraising sums yet. Rep. Michelle Bachmann’s (R-Minn.) campaign, for example, will announce her fundraising numbers July 15.

Still, Bachmann seems unlikely to pass Romney in the second-quarter contest for campaign cash, although she’s likely to outdo the others. Romney has, after all, always been a prodigious fundraiser. In his first bid for the GOP presidential nomination four years ago, for example, he raised $65.1 million and also coughed up $42.3 million of his own money for a campaign loan. Notably, Romney didn’t contribute any of his own money to the fundraising numbers he reported today.

Romney’s also boosted by the help of “Restore the Future,” a super political action committee organized by his former advisers to help him win the nomination. The SuperPAC announced Tuesday it has already brought in $12 million in the first six months.

So, what does all the money mean? The obvious, of course: Romney so far remains the frontrunner for the nomination, with support in all 50 states and the nation’s capital (as the campaign was quick to point out). His campaign finance chairman offered this explanation in a statement: “Voters are responding to Mitt Romney’s message that President Obama’s policies have failed and that we need new leadership in Washington.”

Romney especially has hammered away at Obama’s failed economic policies, drawing some criticism for saying simultaneously that Obama “made the economy worse” and that the nation is in “an anemic recovery” (as though it’s impossible for the two to be simultaneously true!). In a primary sense, it seems to be working: Romney continues to lead in the polls, with a new WMUR-TV poll showing him with a whopping lead of 20 points in New Hampshire.

Rhetorically, Romney seems to already be geared up for the general election, which is just as well, as Obama’s three-month fundraising totals are expected to be in the $60 million range. Of course, as The Fix’s Chris Cillizza has pointed out, it’s not fair to compare primary fundraising with reelection fundraising for a variety of reasons, but, still, that forbidding figure should serve as a reminder to all the GOP candidates as to who they’re really campaigning against and what it will take to win.