A recent Washington Post survey estimated the black turnout in Virginia’s governor’s race at 12 percent, which would be about a 40 percent drop from last year’s general election. Other polling has shown both its and New Jersey’s black population unmoved about the off-year election.

The question at this point isn’t so much whether black voters will turn out at 2008 levels, but how big the drop will be — and then, whether it carries into the 2010 midterms.

Tom Jensen, a spokesman for the Democratic-leaning Public Policy Polling, has been among the most outspoken. He said the high number of Democrats with districts that are significantly black means such a turnout shift could be disastrous for Democrats.

“If what looks like is going to happen in Virginia plays out on a national level, I do think Democrats will lose the House,” Jensen said.