Tom Coburn has heard enough posturing about that $800,000 conference the Government Services Agency held in Las Vegas. He's got a bigger target: The $36 million taxpayers will spend on the Democratic and Republican conventions this summer.

The national party conventions have received public financing since 1976 as part of the post-Watergate campaign finance reforms designed to get dirty money out of politics.  (The parties now also receive millions of dollars from corporations and special interests for their conventions, but that is another story.)

As of May 3, the Republican and Democratic parties have each received checks from the U.S. Treasury for a total of $36.5 million to be spent on their conventions in Charlotte and the Tampa this summer. Four years ago, this taxpayer money went to things like the 200,000 balloons dropped at the Republican convention in Minneapolis and those Greek columns Democrats built in Denver.

Earlier this year, Coburn put the public financing of the conventions as the number one item in his annual "Wastebook" of the most wasteful expenditures of taxpayer money. Now Coburn has written a letter to RNC Chairman Reince Priebus and DNC Chairwoman Debbie Wasserman-Schultz asking them to give the money back.

"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 Priebus and Wasserman-Schultz. "If you agree, I would urge you to reject the millions of dollars of public financing for your 2012 party convention provided by the federal government through the Presidential Election Campaign Fund (PECF) and to return the money to the federal government."

The convention financing comes from a taxpayer fund that comes from the so-called $3 check-off - the little box on your tax return where taxpayers can dedicate $3 of their income tax to go toward public financing of political campaigns.

By law if that money is not spent, it stays in the campaign fund to be used four years later. But a Coburn spokesman suggests that the parties could simply write a check back to the Treasury in the amount they received for their conventions.

Will they do it? Don't count on it. But I have asked the RNC and DNC if they would be willing to give the money back. I have also asked the Obama and Romney campaigns if the money should returned. No answer yet.