Voting rolls, which are maintained by local election officials, are one of the weakest links in American democracy and problems are growing. Republicans have been pressing for sweeping voter purges in many states. They have also fought to make it harder to enroll new voters. Voting experts say there could be serious problems at the polls on Nov. 4. A number of states - including the battleground state of Florida - have adopted no match, no vote rules. Voters can be removed from the rolls if their names do not match a second list, such as a Social Security or driver's license database. But (like the U.S. mail) lists of this kind are notoriously mistake-filled, and one typo can cause a no match. In Ohio, Republicans recently sued the secretary of state, demanding that she provide local officials with a dubious match list. As many as 200,000 new voters could have been blocked from casting ballots. The Supreme Court rejected the suit, but Republicans are still looking for ways to use the list on Election Day. For this election, voters need to be prepared to fight for their right to cast a ballot. They should try to confirm before Nov. 4 that they are on the rolls - something that in many states can be done on a secretary of state or board of elections Web site. If their state permits it, they should vote early. If voters find on Election Day that their names are not on the rolls, they should contact a voters' rights group like Election Protection, at 1-866-OUR-VOTE.