http://finance.yahoo.com/news/buffett-gop-pay-211046623.html WASHINGTON/BOSTON (Reuters) - Warren Buffett is willing to put his money where his mouth is, if only congressional Republicans would join him. The American billionaire investor, in the new issue of Time magazine, says he would donate $1 to paying down the national debt for every dollar donated by a Republican in Congress. The only exception is Senate Republican leader Mitch McConnell - for whom Buffett said he would go $3-to-$1. The idea stems from a New York Times opinion piece Buffett wrote last August in which he said the rich ought to pay more taxes. It sparked an instant controversy, with some Washington conservatives calling on the 81-year-old "Oracle of Omaha" to voluntarily pay extra. McConnell said at the time that if Buffett felt "guilty" about paying too low a tax rate, he should "send in a check." This was quickly followed by introduction of a bill to give taxpayers an option on tax forms to make voluntary donations. "It restores my faith in human nature to think that there are people who have been around Washington all this time and are not yet so cynical as to think that can't be solved by voluntary contributions," the Buffett told Time for an article hitting newsstands on Friday. An aide to McConnell suggested that the Berkshire Hathaway CEO should expand his matching offer to President Barack Obama and his Democrats. "Senator McConnell says that Washington should be smaller, rather than taxes getting bigger. And since some, like President Obama and Mr. Buffett want to pay higher taxes, Congress made it possible for them to call their own bluff and send in a check," said Don Stewart, McConnell's deputy chief of staff. "So I look forward to Mr. Buffett matching a healthy batch of checks from those who actually want to pay higher taxes, including Congressional Democrats, the President and the Democratic National Committee," he added. The jabs over voluntary payments come as higher taxes for the wealthy and extension of payroll tax breaks for middle-class Americans are becoming increasingly contentious issues for the 2012 presidential race. Obama is trying to paint Republicans as only favoring the wealthy, while Republicans are trying to brand the president as relying on tax hikes to fund excessive spending. Buffett said in the Time interview the United States needed a tax system that favored people who were not born investors. "We need a tax system that takes very good care of people who just really aren't as well adapted to the market system, and to capitalism, but are nevertheless just as good citizens, and are doing things that are of use in society," he said. Buffett, who has raised money for President Barack Obama recently, also takes swings at Republican presidential candidates Mitt Romney and Newt Gingrich in the Time interview, criticizing Gingrich's track record and Romney's ties to the private equity business.