AC

Mitt Romney's announcement of a running mate later this summer will kick off a race between Republicans and Democrats to shape the narrative around the new candidate because, according to a new CNN/ORC International poll, most Americans admittedly don't know very much about the contenders. Of those rumored to be on Romney's short list, Marco Rubio is currently the most well-known, the survey showed. Half of those polled said they knew enough about the Florida senator to have an opinion, and 28 percent said they approved of him. But the same doesn't hold true for many of the others: More than 60 percent say they have "never heard of" Ohio Sen. Rob Portman and an additional 17 percent have no opinion of him; likewise 40 percent or more had not heard of Louisiana Gov. Bobby Jindal, Minnesota Gov. Tim Pawlenty and Wisconsin Rep. Paul Ryan. Below are the top line results from the poll, which surveyed 1,517 adult Americans by telephone between June 28 and July 1. The survey has...