It's a rough, but important, measure of how likely a voter is to actually show up on Election Day to cast a ballot.
In 2008 the Democrats had more intensity, now the Republicans do. The party that does not hold the presidency often will have more intensity. It is difficult for an incumbent to meet his supporters' expectations, but easy for him to enrage his opponents.
If you are rooting for the GOP to win, you'll enjoy this column.
