Mitt Romney has a new radio ad running in New Hampshire, in which he boasts of having signed a pledge to not raise any taxes — and even says that he'll eliminate the capital gains tax, at least for the middle class.

"I'm proud to be the only major candidate for President to sign the Tax Pledge. The others have not," Romney says. "I signed the Tax Pledge because I want everyone to know where I stand. We've got to get taxes down and grow our economy. "

Listen to the ad after the jump.