OBSERVING A dispute in the 1950s between two of the Senate's most outspoken if not most followed liberal members, Eugene McCarthy is supposed to have remarked, "Uh oh. Trouble in the leper colony." You might say the same about the latest dispute between two of the most cussed-out organizations in American politics, the Federal Election Commission and the National Conservative Political Action Committee. NCPAC's head, Terry Dolan, has urged that the FEC be abolished; the FEC is currently suing NCPAC on the grounds its "independent expenditures" against a Democrat in 1982 weren't independent at all.

The latest clash between the two occurred last Wednesday in NCPAC's headquarters. An FEC attorney arrived to conduct a deposition -- a questioning, with a stenographer present, of Mr. Dolan. Also present was a reporter from the National Journal. The FEC lawyer refused to take the deposition with the reporter present. The reporter refused to leave, and Mr. Dolan declined to ask him to leave. The FEC lawyer decided not to conduct the deposition, and left.

Pretty silly conduct all around. NCPAC says it wanted the reporter present because it is confident it has acted properly and wants to air the facts; but the facts could also be aired by sending the reporter a transcript later. So give NCPAC demerits (not its first) for staging a publicity stunt.

But the FEC lawyer's conduct is baffling -- and disturbing. "I'm not saying," he admitted, "that we can't disclose the transcript to the press." Then why bar a reporter? Maybe because the FEC, in investigating complaints, is required by law to maintain absolute secrecy: it cannot confirm that a complaint has been received until it takes official action on it. Congress put this provision in the law because it didn't want embarrassing evidence or allegations aired by opponents to come out in campaigns.

But there's no requirement that proceedings be kept secret when the FEC has acted on a complaint by filing a case in court. And there's no good reason to do so when the party against whom the FEC has filed suit has waived any right it might have to secrecy. The FEC is doing the public's business, and it should not let a requirement for secrecy in one part of the law become a fetish for secrecy even where that part of the law doesn't apply.