WASHINGTON - Idaho's lieutenant governor is steamrolling his opponent in the money race for an open U.S. Senate seat by bringing in $636,000 over the past four months.

Lt. Gov. Jim Risch, a Republican, has raised $1.7 million so far in the contest compared with Democrat Larry LaRocco's $785,777, according to campaign finance reports submitted Tuesday to the Federal Election Commission.

Risch has just over $1 million in his campaign account, said Jason Risch, his son and campaign spokesman. LaRocco said he has raised $232,577 over the past four months and has $242,229 in cash on hand in his campaign accounts.

Jason Risch said he and his father were "humbled" by the financial support for the campaign and "encouraged that folks are hearing our message." Risch has loaned his campaign $480,000 so far. The campaign paid him back $130,000 of that money this quarter from donations.

Risch's campaign was openly critical of LaRocco's fundraising Tuesday.

"When you're 15 percentage points behind in the polls, and 4-1 behind cash on hand, it's a financial disaster," Jason Risch said.

LaRocco was more optimistic, saying in a statement that he was "in the position to win" and that it was his best fundraising quarter since beginning his bid more than a year ago for the Senate seat being vacated by Sen. Larry Craig. The campaign has invested in a grassroots network that is beginning to pay off, LaRocco said, characterizing his fundraising as "on an upward trend."

When contacted Tuesday, independent candidate Rex Rammell said that he had loaned $250,000 to his campaign but was on the road and didn't have his full report in front of him. He said he put his own money into the race because, "I think I'm the right guy for the job. Unfortunately, it takes a lot of money to advertise, but I'm willing to do that to win the race."

A full breakdown of donors to all three campaigns was unavailable Tuesday. Unlike House members, who submit their campaign reports online, Senate candidates submit their quarterly fundraising reports in the mail, and the full forms aren't immediately available on the day they're due.

Erika Bolstad: (202) 383-6104