Can Kamala Harris do what was unthinkable a week ago and produce a Democratic presidential win in Florida? In the days since the vice president became the de facto Democratic nominee for president, more and more Democrats — from excited South Florida activists to elected officeholders and state party leaders — have been professing optimism, dreaming of a Harris win. “Florida is totally in play,” declared Randy Fleischer of Davie, who’s been active for decades in Democratic politics.