Opening a new front in the GOP’s ongoing bid to end public campaign financing, Sen. Tom Coburn (R-Okla.) has called on the chairs of the Democratic and Republican National Committees to reject public funding for their upcoming party conventions.

“Can we agree once and for all the party is over when it comes to travel and meetings paid for by the taxpayers?” Coburn wrote today in a letter to RNC Chairman Reince Priebus and to Rep. Debbie Wasserman Schultz (D-Fla.), who chairs the DNC.

Coburn said recent bipartisan calls to end wasteful government junkets such as the $830,000 Las Vegas conference that has made the General Services Administration a target of Congressional scrutiny, should also apply to the party conventions. The RNC convention is scheduled for Aug. 27-30 in Tampa, while Democrats will convene in Charlotte from Sept. 3-6.

“These events will be weeklong parties paid for by taxpayers, much like the highly maligned GSA conference in Las Vegas,” Coburn wrote. “At a time when confidence in Washington has dropped to all time lows and the federal debt is growing by more than $1 trillion a year, we need more than election year rhetoric and political posturing.”

Coburn acknowledged that the two parties are legally entitled to accept $17.7 million apiece to pay for convention costs from the Presidential Election Campaign Fund, which also underwrites the presidential public financing system. But he added that “it would be a great act of statesmanship to return these funds.”

House Republicans enacted legislation in December to end the presidential public financing system and to abolish the Federal Election Commission, but Democrats in charge of the Senate did not take it up.

Enacted with the post-Watergate reforms of the 1970s, the public financing system helps underwrite the party conventions and offers a fixed amount of public money to presidential candidates who agree to spending limits.

For presidential candidates, public financing has lost relevance as campaign costs have escalated, and no major party candidate is expected to opt into the system this year. In 2008, President Barack Obama became the first major party candidate to reject public financing for both the primary and general elections, helping doom the system to irrelevance.

Public financing has also dwindled in importance for the national party conventions, which are increasingly underwritten by private contributions. Still, both Republicans and Democrats are expected to make full use of their public allowances for the Tampa and Charlotte shindigs. Officials for the two major party committees could not immediately be reached for comment.