The D.C. Board of Elections and Ethics violated the free speech of voters by rejecting thousands of petitions to place a slots initiative on the November ballot, the American Civil Liberties Union charged in court papers filed yesterday.

The brief, filed with the D.C. Court of Appeals, asks judges to reverse the board's decision and to place the gambling initiative before voters Nov. 2.

The board of elections was expected to file a brief late last night defending its ruling, which found that more than 6,000 petitions were improperly collected and that petition circulators misled voters.

The ACLU brief is the latest in what is now a legal skirmish over the slots initiative. A local lawyer opposed to slots also filed a brief yesterday supporting the board's decision and accusing petition circulators and slots backers of "pervasive fraud."

The group of business leaders pushing the initiative asked the D.C. Court of Appeals last week to reverse the decision and place the measure on the ballot. Under the plan, a 14-acre site on Bladensburg Road NE would become home to 3,500 video slots machines. The court has scheduled a hearing for Sept. 8.

The board invalidated thousands of petitions after concluding that a five-day petition drive in July was marred by "monumental" flaws. It found that circulators engaged in a pattern of abuses and made false statements about the initiative.

The chairman of the initiative, businessman Pedro Alfonso, has said the gambling hall would create more than 1,500 jobs and generate about $765 million a year in revenue. A quarter of that money would be given to city officials, who would be encouraged to use it for public education and to defray the costs of prescription drugs for the elderly.

In its brief, the ACLU argues that the board overstepped its powers in deciding which petitions were collected legitimately and by ruling that circulators could not make certain statements while seeking signatures.

Art Spitzer, legal director of the ACLU's Washington office, said invalidating petitions because circulators may have mischaracterized the benefits of a slots terminal would be like trying to unseat a victorious candidate because he exaggerated.

"The Board of Elections has asserted the right to regulate political speech for truth and accuracy," the ACLU brief states. The core purpose of the First Amendment "was to protect the free discussion of governmental affairs" from governmental regulation.

Ron Drake, the local attorney who filed a brief supporting the board yesterday, said he was disappointed that the ACLU had joined slots supporters.

"The proponents engaged in pervasive fraud that was so contrary to the concepts of free speech," he said in an interview.

"I'm astonished the ACLU hasn't read the transcript and seen just how bad it was," he added.