There are two possible answers why the "best grass-roots campaign in modern American political history" failed to deliver victory. First, Team Obama's vaunted get-out-the-vote effort was simply a facade. That's not likely, since Milwaukee Mayor Tom Barrett, the Democratic candidate, did receive 158,482 more votes than he did in losing to Mr. Walker in 2010.
The other possibility is the Democrats were out-hustled by the Republicans.
Given the intense focus on the ground game by the Walker campaign, the Republican Governors Association, and Republican National Chairman Reince Priebus (who was Badger State GOP chairman before winning his current post), that's probably a big reason Mr. Walker won with 205,509 more votes than he received 18 months ago.
Before Tuesday's vote in Wisconsin there was already evidence that Democrats nationally didn't have quite the ground game they brag about. Witness the fact that they are so far losing the voter-registration war in the eight battleground or "swing" states (as recognized by the media and the two campaigns) that enroll voters by party.
In Florida and Iowa, Democratic registrations are down from their 2010 levels while Republican numbers are up. For example, nearly 29,000 Democrats have disappeared from the Iowa registration rolls since January 2011, while about 10,000 Republicans have been added.
In Arizona (which Team Obama keeps saying it intends to make a battleground) and Pennsylvania, both parties have lost ground—but Democrats have lost more. In Arizona, Democrats are down 58,000 since the end of 2010; the Republicans are down 9,500. And there are now 176,000 fewer Democrats registered in Pennsylvania than in November 2010, while GOP registrations have dropped by 62,000.
In Colorado, Nevada, New Mexico and North Carolina, both parties increased registrations—but Republicans added more. For example, in North Carolina, there are 17,500 new Democrats registered since January 2011 versus 49,500 more Republicans. This in a state Mr. Obama won by just 14,177 votes in 2008. (All registration numbers come from state websites.)