“If at this point, a voter thinks Obama’s coolness is more important than the fact they can’t get a job, we’re probably not going to sway those people,” says Mr. Collegio. “And there are those people out there.”

But, he and other Republicans point out, not only do polls show that plenty of young undecided voters are open to Romney, but they also show that young voters might not bother to turn out this time. Four years ago, Obama beat John McCain among 18- to 29-year-olds, 66 percent to 32 percent. A Gallup poll this week shows roughly the same margin between Obama and Romney, but only 56 percent of this cohort say they definitely plan to vote. That’s lower than the other age groups.

And coolness does in fact matter when it comes to elections, especially when it’s the presidency, Mr. Fenn says.

“Voting for president is the most personal vote you cast, because you really care about who’s president,” he says. “So you want to make sure there’s a connection, that they’re striking a responsive chord with you.”