the clinton campaign also produced this video featuring republicans. >> we will only really know if he's a real deal or a phony if he releases his tax returns. >> every candidate for president has released their tax returns and donald trump should do as well. >> he doesn't want to do it because presumably there's something in there that's bad. >> trump says he hasn't released his taxes because he's being audited by the irs. the irs says an audit wouldn't prevent trump from making his taxes public. the controversy sparked questions about exactly what's in trump's taxes. one thing we do know, he often bragged about paying as little as possible. >> i said this many times. i pay as little as possible. i fight like hell to pay as little as possible. i try to pay as little tax as possible. i fight very hard to pay as little tax as possible. >> what is your tax rate. >> it's none of your business. you'll see it when he i release but i fight very hard to pay as little tax as possible. joining...