As expected, Mitt Romney is steamrolling all other GOP presidential hopefuls in the dash for cash, according to second-quarter fundraising reports trickling in. But the entire Republican field is pulling in less than it did in 2008, and the eventual nominee will almost certainly be left in the dust financially by President Obama, whose campaign is shooting to raise $1 billion or more.

Mr. Romney’s campaign is expected to report a second-quarter haul of between $15 million and $20 million, while Mr. Obama’s re-election effort has a target of $60 million. Final second-quarter reports, covering April 1 to June 30, must be filed with the Federal Election Commission by July 15.

Even if Mr. Romney, the former Massachusetts governor, who spent Monday marching in several Fourth of July parades in New Hampshire, reports only $15 million, that will still be more than three times as much as his nearest competitors. Former Utah Gov. Jon Huntsman Jr. — who also took part in a New Hampshire Fourth of July parade on Monday — raked in about $4.1 million, and former Minnesota Gov. Tim Pawlenty amassed about $4.2 million, according to the Associated Press...