A day after Mitt Romney was booed at the NAACP convention, Vice President Joe Biden charmed the same audience on Thursday with a spirited speech outlining the successes of the Obama administration. Biden denounced the voter-ID laws taking root across the country that many believe will keep minorities from the polls. And he encouraged the crowd to vote. “When you have the right to vote, you have the right to change things,” he said. He also told the audience that a Romney administration could roll back the gains the black community has made over the past several decades.