The upshot of President Clinton's decision to invoke executive privilege regarding his clemency offer to 16 Puerto Rican members of the Armed Forces of National Liberation (FALN) has been to prompt a constitutional impasse. To be sure, the president's constitutional arguments for privilege are strong. It's too bad, however, that this president has misused this mighty privilege in the past.

And it's also too bad that this Congress has gone astray when it comes to handling sensitive information. The loss of public trust in both branches of government necessitates that both act now to avoid an arcane constitutional clash and instead seek a prudential compromise that recognizes the principled arguments each has advanced. There were welcome hints yesterday of such a possible compromise, at least in the Senate.

Executive privilege, which has a pedigree going back to George Washington, serves several important functions. It prevents disclosure of information that can subvert crucial military or strategic objectives. It affords executive branch officials some privacy. And it ensures that the advice the president gets is candid and frank. As the Supreme Court said regarding President Nixon's invocation of privilege, "Human experience teaches that those who expect public dissemination of their remarks may well temper candor with a concern for appearances and for their own interests to the detriment of the decision-making process."

The FALN case may implicate all three of these functions. Important information relating to the situation in Puerto Rico may be at issue. Privacy concerns could also exist. And publicizing the pardon process will make officials reluctant to give frank advice to the president.

The idiosyncratic pardon context also raises additional concerns that weigh in favor of privilege. People are sometimes reluctant to provide exculpatory information to the pardon attorney if they fear this information will be made public. Reputations, and even lives, might be ruined. As any good prosecutor (or journalist) will understand, promising confidentiality of sources is important. What's more, providing information about FALN will open the door to congressional interference in other pardon matters. Imagine, for example, the Senate opening up the files on Jonathan Pollard.

The Constitution gives the president an absolute right to grant pardons that neither Congress nor anyone else can ever undo. And the practice of the Justice Department for more than 100 years has been not to provide information about clemency to Congress -- at least when that material concerns internal deliberations. Given all this, Congress should think twice before trying to uncover the reasons motivating a particular pardon.

Nevertheless, there are circumstances in which political necessity might demand an explanation. Due to the weighty arguments against doing so, such an explanation should be made only when absolutely necessary, such as when President Ford testified before Congress about his pardon of Nixon. The real question is whether the necessity for piercing privilege in the FALN case is genuine and urgent enough. There are all sorts of allegations about the first lady's involvement, and the White House doesn't have a pure track record when it comes to asserting privilege. President Clinton asserted it in federal courts in Arkansas and Washington to try to prevent information coming out regarding the Whitewater and the Monica Lewinsky matters, but both courts rebuked his assertions, and the White House was forced to drop these claims on appeal.

We are therefore in a quandary: There may be valid grounds for claiming executive privilege, but many don't trust this president's motives given his track record. And so, even with valid grounds, it is a political nightmare to assert it. This hurts everyone -- those who seek pardons, those in the Justice Department who evaluate them and the American public, which lives in doubt of what the president believes.

For its part, Congress says, "Trust us." We won't release any sensitive information. And yet this Congress has had a habit of leaking all sorts of classified and otherwise sensitive material when it suited its ends. Can we -- or this president -- really trust Congress?

Perhaps one way out of this quandary is for the president to follow his predecessors and strike a deal with Congress. After a bitter privilege fight regarding the Environmental Protection Agency, President Reagan voluntarily turned over material to Congress that he deemed covered by privilege.

Now that both sides have taken their political hits, President Clinton should provide the documentation on two conditions. First, that the material remain appropriately confidential -- perhaps given only to the chair and ranking member of the relevant committees. Second, that Congress publicly recognize that the documents are protected by executive privilege. This solution would acknowledge and address Congress's worry about this unique and troubling matter, while also honoring the president's compelling concerns about precedent and principle. If both sides work together and realize that each has to give to make up for past wrongs, as perhaps is now occurring in the Senate Judiciary Committee, maybe trust can be restored.

The writer is an associate professor at Georgetown University Law Center.