Letterman: Romney 'A Felon' Who 'Hasn't Paid A Nickel In Income Tax' David Letterman "Americans would most like to see: six percent said Mitt Romney's tax returns." "Yeah, we want to get a look at those tax returns, because I believe we will discover that the man has not paid a nickel in United States federal income tax." "That’s right, we have a felon running for president."