WASHINGTON (AP) _ The American Civil Liberties Union sued Attorney General Edwin Meese's Commission on Pornography on Thursday, accusing the panel of violating federal law by withholding from the public drafts and working papers that will be used in preparing its final report.

The U.S. District Court suit seeks to enjoin the commission from conducting any business until it agrees to release the documents, which include a study on possible links between pornography and anti-social behavior and documents on the cable television industry and pornography.

The ACLU said the commission and the Justice Department are violating the Federal Advisory Committee Act requiring maximum openness and disclosure.

Dee Kuhn, a Justice Department spokeswoman, said in response that the documents can be withheld under an exemption in the Freedom of Information Act and that ''we'll fight the suit in the courts.''

Justice Department officials ''seem to have become so obsessed with restricting what other people can see and read about sex that they now have started to censor their own writings on the subject,'' ACLU legislative counsel Barry Lynn told a news conference.

''The attorney general has ... begun an insidious form of censorship over the members of the pornography commission so that they may not disclose the drafts, working papers, studies and other documents which really are the essential supports for any final report to be issued by this body,'' Lynn added.

According to documents filed in the case, Alan E. Sears, a federal prosecutor who is the commission's executive director, told the panel Feb. 28 that drafts and working papers no longer would be released to the public. Sears subsequently told the ACLU in a letter that the documents can be kept secret under an exemption in the Freedom of Information Act.

Kuhn of the Justice Department said the ACLU has ''been able to see all the transcripts, testimony, it's been wide open. But once any staff gets down to writing drafts for the commissioners' decision, these are pre-decisional documents and as such don't have to be released.''

The commission's final report is expected in June and its last meeting is the end of this month.

The panel's policy switch came just five days after the ACLU issued a report describing the commission's proceedings as biased, unfair and intellectually indefensible. The ACLU based its findings on until-then publicly available commission working papers.

The ACLU said at the time that the commission had tentatively decided to recommend a wide-ranging government crackdown on obscene material, including an attack on X-rated films by means of laws against pandering and prostitution.

Under the revised policy, the public still can attend commission meetings and file comments with the panel. But access to drafts and working papers is vital to understanding what the commission is doing, the lawsuit said.

''A commissioner could say 'I support option A for the reasons stated in paragraph 1 of page 10' and the people who are sitting in that meeting won't know what's going on,'' said Patti Goldman, a lawyer with Public Citizen, an activist group founded by Ralph Nader that is representing the ACLU in the case.

Lynn of the ACLU said the panel is withholding documents relating to the issue of regulating cable TV, and the question of whether ''to support or not to support development of federal indecency standard for cable programming.''