DES MOINES, Iowa (AP) — A catchy political ad and a gotcha video have raised Republican hopes of capturing the Senate seat in Iowa, a prospect that would greatly enhance the party's chances of regaining control of the Senate. [...] if no GOP candidate gets more than 35 percent of the primary vote, the nominee will be selected at a potentially divisive state GOP convention. Two days after Ernst's ad appeared, a conservative political action committee released amateur video of Braley's comments in Texas that he would better represent lawyers than "a farmer from Iowa who never went to law school, never practiced law." Besides Ernst, an Iraq War veteran, the GOP field includes former energy company CEO Mark Jacobs, who already has run more than $350,000 in television advertising — vastly more than his opponents — including a spot attacking Braley's comments about Grassley. Other candidates are former U.S.