WASHINGTON (CNN) -- The Democratic Party on Monday filed a lawsuit against the Federal Elections Commission seeking to force the group to investigate whether Sen. John McCain has violated federal spending limits for his primary campaign.

The lawsuit, which was filed in the United States District Court in Washington, is the latest move by the Democratic National Committee that seeks to prove the Arizona senator locked himself into campaign spending limits earlier this year.

The DNC claims McCain did so when he used the prospect of $6 million in federal matching funds as collateral for a December bank loan to his campaign.

But after it became apparent he would be the Republican presidential nominee, McCain notified the FEC in early February that he was not claiming federal matching funds. Claiming those funds would limit his spending on the primary campaign to $54 million. Watch more on the public financing controversy »

The DNC then filed a complaint with the FEC in February, arguing that McCain should be forced to accept the matching funds -- and the spending limits that come with it.

DNC Chairman Howard Dean said that McCain not only used the prospect of the funds as loan collateral, but he also accepted automatic ballot access in every state -- an advantage given to those who accept federal matching funds. Those who do not accept federal matching funds are forced to gain ballot access themselves -- a task that can cost millions of dollars.

McCain, a chief advocate of campaign finance reform, sought the option of public financing last fall when his campaign was in dire need of money.

The primary campaign officially lasts through the party's convention at the end of the summer. FEC filings show McCain spent close to $60 million through the end of February, meaning a ruling in DNC's favor would essentially leave McCain unable to campaign for the presidency over the next five months.

"Despite Sen. McCain's apparent belief that the reforms he championed apply to everyone but himself, there is a compelling public interest in determining whether Sen. McCain agreed to participate in the matching funds program so he could get a loan for his campaign, then violated the terms of that agreement so he could ignore the spending cap and raise unlimited money from lobbyists and special interests," Tom McMahon, the DNC's executive director, said in a statement Monday.

The Republican National Committee called the lawsuit "total nonsense."

"It is now clear that the trial-lawyer Democrats' idea of campaigning for president is to hire lawyers and file frivolous lawsuits," RNC spokesman Alex Conant said. "It's unfortunate the DNC is now trying to drag the federal courts into their circus as well."

According to FEC rules, the body has 120 days to act after a complaint is filed before court action can be taken. Less than half that amount of time has passed since the complaint was filed in February.

But the FEC is currently hamstrung by vacancies -- four of the commission's six seats are empty, and a deadlock between President Bush and the Senate has stalled nominees for those posts. With the absence of a quorum, the body is unable to act on any complaints filed.

The DNC says it hoped the lawsuit will compel the FEC to take action, but in the likely event the commission continues to lack a quorum, it will seek to sue McCain's campaign directly.

The lawsuit comes just days after McCain criticized Sen. Barack Obama for appearing to back away from his initial indication he would accept public matching funds for his general election campaign. McCain himself has left the option open of accepting matching funds this fall. Watch more on where the candidates are getting their money »

"He committed to it," McCain told reporters on Friday. "So in direct contradiction to his rhetoric, he's now saying well he may not do it. So facts are facts. Facts are stubborn things.

"I repeat my commitment to public financing if he will, and I call on him to keep his commitment that he made a year ago, and not flip-flop.

Obama has raised more than $230 million from about 1.3 million donors on the Internet since his campaign began last year.

McCain has raised approximately $80 million in the same period.

Should Obama and McCain accept public financing, they would be granted $84 million by the federal government and would be unable to spend any more. E-mail to a friend

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