Can the trial of Lt. Col. Oliver North on charges growing out of the Iran-Contra scandal be conducted without exposing vital U.S. secrets?

That question - rather than North's guilt or innocence - is rapidly becoming the center of the whole case and will have to be resolved before the trial opens next January.As matters now stand, the White House and U.S. District Judge Berhard A. Gesell seem to be trying to make each other responsible for whether or not the trial proceeds.

Last week, Judge Gesell left the door open for President Reagan to halt the trial, saying that if certain secret documents and other testimony are perceived as a threat to national security then the chief executive has various courses he may take.

This week, President Reagan ruled out a pre-trial pardon for North but refused to release some 40,000 pages of secret documents that the colonel's attorneys want to use in North's defense.

This situation puts the ball back in Judge Gesell's arena and sets the stage for the possible dismissal of some or all of the felony charges pending against North.

The major charges facing North include conspiracy, carrying on a secret operation that subverted the original arms sale to Iran idea; diverting profits from the sales to help Contras in Nicaragua in defiance of a congressional ban on such aid; and stealing government property - the profits from the arms sales - and giving it to the Contras.

Under the law, the judge can now order the prosecution to give North some or all of the details he wants. But the Justice Department can legally refuse to supply the information even if the court deems it essential to North's defense.

Should the Justice Department refuse, the judge then has several options: 1. Order dismissal of the entire indictment or certain counts in it; 2. Strike or preclude a particular witness's testimony; 3. Simply rule against the prosecution on any of the issues underlying the contested secrets.

What a difficult can of worms. The full case against North can't be pursued in court without exposing secrets whose disclosure could hurt the U.S. Yet, just as a premature pardon would thwart justice, aborting the trial on national security grounds woud incur suspicions of another coverup.

Is there no way out of this bind? Possibly, if the country is willing to abandon the notion that North must either be tried on all the charges against him or none at all. Specifically, there's room for thinking that secret documents might not have to be disclosed in trying North on the lesser charge of trying to conceal from Congress his role in the Iran-Contra scandal. This charge should not be dropped even if others are.

If North can be convicted of nothing more serious than illegally shredding documents sought by congressional investigators, then he should be treated as toughly as possible on this score. Other Americans in sensitive posts should not be encouraged to think they can bend the rules and get away with it just because bringing them to justice would involve exposing important secrets.