Donald Trump is leading by 2 points in a new Florida poll. He's spent 3 straight days campaigning in the Sunshine State. CBS News' Major Garrett explains how crucial it is for the Trump campaign to maintain that lead. Garrett also reports on the effect Obamacare premium hikes are having on the race. He says the trouble with the president's signature law could hurt Democratic candidate Hillary Clinton, but the longer Trump focuses on it, the more likely he is to face a question he is not equipped to answer.