Two Republican presidential candidates — former House Speaker Newt Gingrich and former Massachusetts Gov. Mitt Romney — appeared Wednesday at a forum sponsored by Univision and the Hispanic Chamber of Commerce. Also Wednesday, prominent Latino politicians, including Florida's Republican Sen. Marco Rubio, called on Gingrich to take down a new radio ad that calls Romney "anti-immigrant." The Gingrich campaign complied and pulled the ad. Melissa Block talks with NPR's Greg Allen in Miami.