An honest and deeply felt disagreement between newsmen covering the Pentagon draws aim on the Freedom of Information Act, which has opened some otherwise closed government files.

Under the FOIA, anyone can request copies of unreleased government documents. While the release process is cumbersome, and reluctant government agencies can engage in tedious delay, the act, on balance, has provided public access to significant information.

The newsmen's argument started when, in the course of producing a series of articles on the military, Jack Taylor of The Daily Oklahoman discovered that the Army records with it calls after-action reports on reporters' interviews. Public affairs prepare these reports, and they contain information on places the reporter visits, officials interviewed, issues raised and, sometimes, comments on reporters.

After Mr. Taylor learned of the reports, he was asked by Investigative Reporters and Editiors Inc. to lead to a panel discussion on how the Pentagon handles the press.

Once after-action reports are produced, they become government documents and there fore are fair game for requests under the FOIA. So Mr. Taylor requested copies of a number of the reports, all of them on other reporters' interviews.

Reagan from competing reporters has been predictably anguished. John Fialka, who covers the Pentagon for The Washington Star, has become the point man for those who oppose the reports' release.

Mr. Fialka makes some very strong points. If an investigative reporter's interviews are made available to other reporters, why would editors approve the time, effort and money required to undertake the difficult business of developing information for a complex series of news stories?

To paraphrase Mr. Fialka, there is not enough investigative reporting now, and to have one's early research revealed to the competition would have a chilling effect on what is already a difficult process. Furthermore, Mr. Fialka maintains, there is a proprietary right involved. A newspaper that assigns a reporter to spend weeks or months on his story has a right to publish the results before his sources are forced to reveal his initiative to other reporters.

The IRE committee supports Mr. Taylor. The Reporters Committee for Freedom of Information is polling its board to arrive at a position.

Meantime, the Army has taken the middle ground. Its general counsel decided in January that it would release after-action reports after the substance of an interview has been published, not before. Mr. Fialka argues with the Army's position. He says that a reporter's research might appear even years later and must have permanent protection.

Compromises have been proposed. The IRE committee has suggested that the Army be prevented from making the after-action reports. Others argue that the reports are strictly the Army's business and can be handled any way the Army wishes.

But when all differences are in, the press faces an unavoidable decision, a Catch-22. Either agree that after-action reports are releasable under the FOIA, or seek an exemption to protect its own interviews.

Stark confrontation that it is, it seems to me that the press cannot make the latter decision. It must rely on its own devices and journalistic ethics instead. To ask for an exemption to the act would undermine the perennial and inevitable stance the press must take: that all possible government information has to be made available for public consumption.