Two sponsors of the nation's campaign finance law sued the Federal Election Commission (search) on Tuesday for failing to block the spending of unlimited donations in the presidential race, the second lawsuit the FEC has faced over the issue this month.

The lawsuit filed in federal court in Washington by Reps. Christopher Shays (search), R-Conn., and Martin Meehan (search), D-Mass., accuses the agency in charge of enforcing campaign finance regulations of failing to do its job.

"The commission has once again 'subverted' the law," the lawsuit says. It asks the court to order the FEC to adopt rules limiting fund raising and spending by groups active in federal races.

Shays and Meehan were the lead House sponsors of a campaign law in effect for the first time this election cycle that broadly bans the use of "soft money" (search) -- corporate, union and unlimited contributions -- in presidential and congressional races. The Senate sponsors, Sen. John McCain, R-Ariz., and Russ Feingold, D-Wis., planned to file briefs supporting the lawsuit.

President Bush's campaign wants a federal judge to order the commission to act on complaints the campaign filed in March against various anti-Bush groups spending tens of millions of dollars in soft money in the presidential race. The groups contend their activities are legal.

In the months since the anti-Bush spending began, several anti-Kerry organizations have popped up to spend millions of dollars in soft money in the presidential race.

U.S. District Judge James Robertson planned a hearing in the Bush lawsuit on Wednesday.