9:15 p.m.:

Maine's supreme court overturned a lower court ruling today and said a single faulty signature can invalidate a whole page of a candidate's nominating petition. The decision effectively removes independent Herbert Hoffman's name from November's U.S. Senate ballot.

The Maine Democratic Party, which challenged Hoffman's petitions, called the ruling a victory for the rule of law. Democrats were concerned that Hoffman, a former Democrat, could have drawn votes away from their party's nominee, Tom Allen, the 1st District congressman who's attempting to unseat Republican Sen. Susan Collins in a race that is drawing national attention.

Herbert Hoffman's campaign said it was "shocked and surprised" by the decision.

"We have to study it. We don't know what our next step will be," said campaign Manager Lynn Ellis.

9:31 a.m.: Nov. ballot ruling expected

Maine's Supreme Court is expected to rule today on Democrats' efforts to remove Senate-hopeful Herbert Hoffman's name from the November ballot.

The secretary of state already ruled that Hoffman collected enough signatures to appear on the ballot, and a Superior Court justice agreed. But the Democratic Party appealed to the state's highest court.

The party contends Hoffman violated rules because he was not present when three registered voters signed one of his petitions. Democrats fear Hoffman could draw votes away from their party's nominee, Rep. Tom Allen, who's attempting to unseat Republican Sen. Susan Collins.

The Associated Press contributed to this report