Will the three percent who are still undecided ever decide?

With three weeks to go, a tiny three percent of the US population say they are still not sure who they plan to vote for. Will they ever decide?

How do you stay undecided so long? Are these people that just find it incredibly difficult to make up their minds? Is it that they haven’t any idea what they stand for and so they can’t select the candidate that most closely matches their positions? Are they just so unconcerned about the race that they don’t actually know who is running or what they stand for, and therefore will never decide and will never vote?