the story is false. to take an ex-wife and make it two days before the primary a significant question of a presidential campaign is as close to despicable as anything i can imagine. reporter: mitt romney had learned he lost the january 3rd caucuses to rick santorum. i had to work to get 25 more votes in iowa, that s for sure. reporter: now rivals are slamming his business takeovers that led to firings. i find it kind of strange on a stage like this with republicans having to describe how private equity and venture capital work and how they re successful and how they create jobs. reporter: he paid a 15% income tax rate but hasn t released his returns. gingrich did tonight. $3 million in income in 2010 and a tax rate of 32%. but santorum wants a race against romney. newt s in the way. grand yosity has never been a problem with newt gingrich. he hands it very, very well. you re right. i think grandiose thoughts. this is a grandiose country of big people doing big