What makes Mitch McConnell smile?

Aired: 11/3/2014 | 0:01:56 | Clip
While incumbents usually have the advantage in elections, this midterm season has been a boon for Republican challengers. The most competitive Senate races are being run in blue or purple states that voted for Gov. Mitt Romney in the last presidential election. NewsHour’s political editor Domenico Montanaro breaks down the Republican advantage for Tuesday.