With Florida’s pivotal Republican primary four days away, Mitt Romney and Newt Gingrich spent Saturday dueling across the state, trying to convince voters their opponent is unfit to be president.

Romney, who has built a commanding Florida lead, released a scathing new ad reminding voters how the House of Representatives overwhelmingly reprimanded Gingrich for ethical lapses while he was speaker.

Gingrich’s campaign fought back Saturday, calling the ad “false,” labeling Romney “dishonest,” and vowing to “go all the way to the convention,” regardless of the Florida result.