PRESIDENT REAGAN trespassed a bit further on the freedom of the press last week when he ordered a Justice Department probe to discover who, among top administration officials, had leaked information that had jeopardized the safety of the administration's new top envoy to the Middle East Robert C. McFarlane. The President alleged that leaks about air-strikes--employed to ensure the safety of U.S. Marines in Lebanon--had endangered both McFarlane'x peace efforts and his personal safety. The FBI began questioning officials, cabinet members and foreign policy advisers, some of whom offered to take polygraph tests to insure that they weren't lying. But Reagan should realize that there is a limit to how much he can stem such leaks. They are a symptom not of a disloyal staff but of a free society and an open democracy where the governed as much as the government set the agenda for discussion.

The current investigation brings to mind former Secretary of State Henry A. Kissinger '50's reaction in a panel discussion about the controversial film "The Day After." "I wrote the book on this issue 30 years ago, why discuss it now." Kissinger seemed to say, reaffirming his old leader's attitude towards the country's right to know. But discussion-unfortunately for an administration that believes in talking little and acting precipitously--is one of the basic tenets of democracy. The government is not empowered to decide when the public should think an issue important and how they should view it. The government is only empowered to govern. When an issue is top secret, then and only then, with a certain dependence on the discretion of journalists, can the government in effect censure the right of journalists to print stories.

Not only is such a crackdown unjustified and inefficient, it also has a demoralizing side effect. Art Buchwald, in his latest book, jokes about an administration official who lunched with a reporter to find out what his department was doing. The government's attempts to keep its operations secret have created situations such that informed journalists know more about what happens in the government than the government itself. It was sad to discover that when journalists asked spokesman Larry Speakes about the Grenada invasion, he was forced to lie, not knowing that the invasion was at that moment taking place. One official in the administration's press office found the arrangement so unpleasant that he resigned.

It is true that the government must filter and limit information that will directly endanger government representatives. But this idea is nothing new to the business of governing a democracy, and reporters have long understood the need for such discretion and have long cooperated with the government in such endeavors. But if the government persists in attempting to keep the country in the dark, it should expect some form of retaliation.

Yet the President continues his efforts to discredit the press, whom he continually accuses of creating hype and hoopla over his activities. He holds limited and well-screened press-conferences and seems to feel that all the press is owed is statements, not explanations. He triex, through his television appearances, to be his own press expecting that the public will view the newspapers as some from of Democratic faction, since it refuses to sanction his activities.

THE PRESS, however, is a neutral unit. Remaining as well informed as it can be, the press functions as a sort of watchdog, putting in perspective the actions of the country at large. The country at large is then well trained in understanding what is hype and what isn't. We filter the information we receive and then turn to the analysis we want to choose. We are free to subscribe to the New Republic or the New Statesman, depending upon our opinion.

The government's investigation of its staff must be seen as another grave effort on the part of the President to prevent democracy from cramping his style, an effort that cannot be interrupted. The War Powers Act, for example, allows the president the right to use forces without a declaration of war under an examination period of 60 days. With that kind of freedom for the chief executive, the country cannot remain uniformed. Certainly we should allow the government the right to protect national security interests, but even that right must come under scrutiny if, amidst all sorts of challenges from the country, the administration persists in facing down the country's right to know.

The ones of the protection of national security interests now lies in the court of the government, not in that of the press. If the government reverses its policy and makes a profound effort to cooperate with the press, then, and only then, can the government expect the country to respond with trust. But the government has broken that trust and placed the press in a position of conducting an all-out war to accurately inform the country. It is up to the administration, through careful cooperation with the press to keep national security interests intact. Otherwise, the best we can hope for is that the next time the President appears on national television, he too will be wearing a lie detector.