Where reporters must draw the line

George Will's approving critique on TV of Ronald Reagan's debating performance - after having helped Reagan with his 1980 debate preparations - has already evoked a considerable amount of criticism. And rightly so.

But those who know Mr. Will regard him as an honorable man who simply made a mistake - one which he concedes. This will thus be a helpful learning experience as he moves forward in what already is a brilliant journalistic career.

The Will case does cause fellow journalists to examine their own conduct and those of their colleagues in dealing with public figures. The old question many are raising in their own columns is: How close can a reporter get to his news source without stepping over the ethical line?

The great Walter Lippmann was not only an adviser of presidents - he also commented freely on presidential actions that were taken in response to that privately given advice. Several reporters were quite open - and proud - about their particularly close personal relationship with President Kennedy. Observers found it not surprising that those who were intimate friends of Kennedy often wrote favorably about him.

Usually one heard words not of criticism but more of envy from other reporters in talking about newsmen with inside pull.

But since Watergate, which caused a thorough-going examination of the ethics of those involved in making and reporting the news in Washington, some higher standards have emerged. Today there are post-Watergate ''purists'' among Washington reporters who express the view that the journalist should stay completely detached from a news source. They argue that this is the only way an incestuous relationship can be avoided.

Yet, from a practical standpoint, such detachment seems bound to end up in a reporter not being close enough ''in'' to find out what really is going on.

Most news media people in this city take the position that a reporter's job is to get close to subjects but not so close as to lose his or her professional detachment. They see the closeness as necessary lest their publication lose some good stories to a competitor whose reporter has established this closeness. But they maintain that, difficult as it may be, it still is possible - and necessary - for the reporters to walk on the side of ethical detachment.

Can a reporter ever give advice to a public figure without stepping over the line of impropriety? Rarely. Once a presidential candidate asked a reporter to tell him how he could get along better with the press corps following him around the country. In this instance, the reporter decided that he could respond since this could help his fellow reporters.

So he advised the candidate to make himself more available to the reporters, and also to react less often and less angrily to stories he felt were not sufficiently favorable to his campaign. Even that counseling stepped dangerously close to the line because it was inevitable that the reporter after a while would have to size up the candidate's press relations. And if he wrote about them approvingly, he would in effect be commenting favorably on the advice he had given.

Once Adlai Stevenson, nettled over press coverage from those in the campaign entourage, met with reporters and invited advice on how he could serve them better and get along with them better. What he was after was, of course, a ''better press.'' Under such circumstances, the reportorial advice that was given could be described as press-oriented: Those reporters were not trying to help Stevenson's campaign but to persuade him to respond to their needs.

In any case, reporters can learn a lot from Mr. Will. They can be reminded to resist the flattery of becoming advisers to important public figures lest they risk eroding their own professionalism.