Polarized America

This is a great WashPost article that looks at the polarization of state governments and how they govern so differently if they are blue, red, or mixed states.  It also has a great interactive image that lets you see how long a state has gone one way or the other.  Not only can this be used when you discuss federalism, but it can be looked at when you look at running for president as its grey states (most places would color them purple) already show where the 2016 candidates will have to campaign.