Why Republicans should start panicking, in 1 chart

Midterm elections are about one thing: Base enthusiasm.

Unlike presidential elections -- where casual voters dial in and turn out -- midterm elections, historically speaking, tend to be the dominion of only the most committed party warriors. And those most committed party warriors almost exclusively hail from the extreme edges of both the Democratic and Republican coalitions -- i.e. the most liberal and the most conservative elements.Which brings me to the chart above. It's from a brand new national Pew poll and shows one thing very clearly: The D...