Because Michigan held its primary before Democratic National Committee rules permitted, the DNC stripped the state of its delegates to the party convention. The candidates boycotted the state, and Obama's name did not appear on the primary ballot.
The Hillary Clinton campaign seized on the decision to urge the Barack Obama campaign to support a new, party-run primary, the results of which would ostensibly replace the Jan. 15 primary results.
"Michigan voters must not be disenfranchised and the Obama campaign must not continue to block Michigan's efforts to hold a new vote," Clinton campaign manager Maggie Williams said in the statement. "Rather it should move quickly to announce its support for a party run primary."
As CBS News chief political consultant Marc Ambinder notes, the ruling does not mean that a new primary must be held – the judge left that question up to the parties themselves.
"...the ruling today means nothing more than a chance for her to make the case again for a re-vote," Ambinder writes.
The Clinton campaign has been pressing for a revote in the hope that delegates from Michigan (as well as Florida, a state similarly penalized) would help her close the delegate gap on Obama. In the latest CBS News delegate count, Obama leads Clinton 1618 to 1491.