Republican Clint Didier has raised more than $570,000 for his underdog campaign for the U.S. Senate, according to his latest campaign-finance filing with the Federal Election Commission.

Didier, the former tight end for the Washington Redskins and a Pasco farmer, credited the endorsement of Sarah Palin for helping him bring in $220,000 during the second quarter.

The Didier campaign received only two checks from political action committees, according to a spokeswoman: $5,000 from Palin's PAC and $2,500 from Freedom's Defense Fund. Didier said he received many small donations from regular folks.

"I am so humbled and proud that so many people are sending me their hard-earned money. We're seeing $5 and $10 donations from people who say they wish they could send more," he said in a statement.

Didier told me Wednesday (I spent the day on his farm for an upcoming profile) that he still expects Palin to headline a fundraiser for him some time in August.

He'll need all the help he can get, with GOP frontrunner Dino Rossi reporting $1.4 million in contributions in little over a month and incumbent Democratic Sen. Patty Murray's campaign sitting on $6.8 million.

Didier's FEC report shows he's spending most of his money to try to get past the Aug. 17 primary. He reported just over $100,000 cash on hand at the end of June (the close of the second quarter).

Rossi, meanwhile, is banking most of his money for a presumed November matchup with Murray. His campaign says he had more than $1.3 million cash on hand at the end of June.

Meanwhile, Republican Bellingham businessman Paul Akers' campaign says he has spent about $500,000 on his campaign. Most of that is his own money, as he reported about $60,000 in contributions.