A judge ordered Michigan election officials Monday to stop canceling a voter's registration if the card is returned as undeliverable.

More than 1,400 people in that category have been disqualified so far in 2008, although it's unclear how many cancellations were actually wrong. Some people may have moved or left the state.

Nonetheless, it's a violation of federal law, U.S. District Judge Stephen Murphy said, ruling in a lawsuit filed by the American Civil Liberties Union and a group representing college students.

Murphy said nothing should prevent those voters from casting a ballot if they can produce additional proof of residency at the polls.

"It does sound like good news," attorney Bradley Heard said. "Nobody should lose their right to vote because they didn't get a piece of mail."

The judge also found that Michigan is violating federal law when it cancels a voter's registration when that person applies for a driver's license in another state.

"The appearance of an out-of-state address on a driver's license application simply does not establish that the applicant is no longer an eligible Michigan voter," Murphy said.

But the number of people, he added, probably is small.

"We're still reviewing the ruling with our attorneys to see what our next steps will be," said Kelly Chesney, spokeswoman for the Michigan secretary of state's office, which handles elections.

Murphy said officials must go back as far as Jan. 1, 2006 to remove "rejected" markings from registrations tied to undeliverable voter cards, unless there was another legitimate reason for spiking them.

Given the unprecedented amount of resources Barack Obama’s campaign poured into voter registration efforts, the decision will likely help the Democratic presidential nominee. The University’s chapter of College Democrats registered about 4,000 new voters on campus before the Oct. 6 deadline.

While the total number of registered voters in Ann Arbor hasn’t been determined, Ann Arbor City Clerk Jacqueline Beaudry said in an interview last month that she expects the number of registered voters in Ann Arbor to be much higher than in previous election cycles.

Nathaniel Eli Coats Styer, chair of the University’s chapter of College Democrats, said the decision would help Obama win the state’s 17 electoral votes because it will keep newly registered voters — many of who are students who support Obama — on the voter rolls.

“This is huge for students,” Styer said. “It strikes down any Republican attempt to purge the voter rolls. Both of these things are things that impact students and low-income families.”

Styer said he’s received reports from representatives of Barack Obama’s campaign that a large number of new Ann Arbor registrants were taken off the voter list after their voter identification cards were returned as undeliverable.

Styer said that there are many reasons a voter identification card returned from a residence hall address as undeliverable. If a person’s room number isn’t included on the card, Styer said the front desk clerk might have it returned to the post office.

Brady Smith, chair of the University’s chapter of College Republicans said he thought the decision means more people could fraudulently cast ballots.

“It’s a complex problem,” Smith said. “It looks like you really eliminated one of the best ways we have of identifying multiple votes and really voter fraud.”

— Daily Staff Reporter Julie Rowe and The Associated Press contributed to this report.