Which side does it favor now? We can look for clues in the turnout in the primaries for governor in New Jersey and Virginia earlier this month.

In New Jersey, Republicans had a vigorously contested primary, and turnout was down 2 percent as compared with their last serious contested primary for governor, in 2001. Not a good sign, along with evidence that some conservative voters have been fleeing this high-tax state. Democrats didn't have a serious contest and haven't had one in a dozen years. But their turnout was down 18 percent from 2005 and down 26 percent from 2001. It fell especially in the densely populated urban northeastern counties, where Democratic incumbent Jon Corzine, with his low job ratings, needs high turnout in November. It looks like the balance of enthusiasm is working against him.

Virginia had only a Democratic gubernatorial primary, in which 318,000 people voted. That's 35 percent fewer than the 493,000 who voted in the last gubernatorial primary, way back in 1977, and 68 percent fewer than the 986,000 who voted in Virginia's Democratic presidential primary 16 months ago.

Obviously many people regard an election for president as more important than an election for governor, and the contest between Barack Obama and Hillary Clinton did arouse genuine enthusiasms that far outshone anything the Republicans could muster last year. And nominee Creigh Deeds won a come-from-behind victory that usually produces a bump.

But if I were the Democrats, I'd be worried about the balance of enthusiasm. If I were the Republicans, I'd be mildly optimistic.