John McCain committed a malicious misrepresentation in the last presidential debate when he claimed that ACORN, the liberal activist group, “is now on the verge of maybe perpetrating one of the greatest frauds in voter history in this country, maybe destroying the fabric of democracy.”

As ACORN acknowledges, it has collected voter registration forms with bogus signatures. But even when they aren’t winnowed out by election officials, transparently invalid registrations don’t lead to fraudulent voting. Even the most lax poll worker wouldn’t allow “Mickey Mouse” or “John Q. Public” to cast a ballot.

There’s a case to be made for cracking down on errors and, yes, fraud in election procedures, and the FBI reportedly is conducting a preliminary investigation of whether ACORN, the Assn. of Community Organizations for Reform Now, encouraged its canvassers to falsify signatures. But wild claims like McCain’s undermine reform efforts and make it harder to hold ACORN accountable for its real faults, including providing a financial incentive for canvassers to fake signatures. (A commission chaired by former President Carter and former Secretary of State James A. Baker III recommended in 2005 that states engage in special scrutiny of registration forms turned in by third-party organizations that pay their canvassers.)

Swamping election agencies with obviously phony registrations distracts officials from the serious business of verifying other registrations, as contemplated by the Help America Vote Act approved by Congress in 2002. That law, which figured in a U.S. Supreme Court ruling last week, requires states to establish a “centralized, interactive, computerized statewide voter registration list” that “shall be coordinated with other agency databases within the state.”

To its credit, California tries to match registrations with both driver’s license records and the last four digits of Social Security numbers. If there is a mismatch, county election officials contact the potential voter to verify his or her status. The problem isn’t obvious examples of fraud, such as a “Mickey Mouse” signature, but the possibility that a real person is registering multiple times or seeking to vote where he no longer lives.

The debate about election fraud is complicated by the fact that the political parties have different priorities. Democrats emphasize increasing the number of voters, particularly the poor and minorities, and too easily dismiss the possibility of fraud. Republicans claim to be concerned about widespread fraud, but aren’t bothered if their alarms discourage Democratic-leaning blocs from voting. What’s needed is a commitment by both parties to take both fraud and voter suppression seriously.