The commission of inquiry into the Maher Arar case promises plenty of courtroom drama in the months to come. Lawyers spar with witnesses and each other, while a kindly but iron-handed judge passes verdicts on procedure. But this isn't Law & Order territory. On trial is Canadian national security in a post-Sept. 11 world. We haven't had such a scene for a quarter of a century, not since the McDonald Commission raised the lid on the RCMP Security Service's secret practices.

The government insists that Canadian officials did no wrong in the Arar case. What makes the government really squirm is public scrutiny of the inner workings of the security and intelligence services. Having reluctantly backed into a public inquiry, the government intends to throw a strong defence around the protection of secrets. The first week has seen many instances of national-security confidentiality being claimed to shut down lines of questioning. The most blatant example was the deletion of every single word in a recent Security Intelligence Review Committee (SIRC) report summarizing its own investigation into the role played by the Canadian Security Intelligence Service in the Arar case. Matters of national security, it seems, include words such as "and" and "but."

The commission will have recourse to in camera hearings, where secrets can be aired. But how much will ultimately be revealed in the promised public report? No deadline for its production has been set.

The Arar inquiry commissioner, Mr. Justice Dennis O'Connor, will ultimately have to make a Solomonic judgment on the proper balance between protecting national security and the public right to know. He has a Solomonic helper at his side in Ron Atkey, a former cabinet minister and former chairman of the Security Intelligence Review Committee, who is unlikely to be too impressed by top-secret labels. Judge O'Connor's powers under the Inquiries Act are strong, but not total. While he can compel testimony and the production of documents, the government holds the final trump card. The Attorney-General can lay down a definition of national security confidentiality that cannot be contested short of a Charter challenge.

Judge O'Connor faces another difficulty, partly of his own devising. He has opened the door to a full airing of the many mythologies that flourish around Canadian security and intelligence practices. Mr. Arar's lawyer, Lorne Waldman, given a leading role in the questioning of government officials and other witnesses to be called, has played tough cop to the commission's own counsel, Paul Cavalluzzo. Mr. Waldman clearly intends to press his contentions that Canadian officials have been complicit in contracting out torture, engaging in blatant racial profiling and turning a blind eye to using confessions obtained under torture.

This will certainly add to the drama of the proceedings, but will it will add to the uncovering of truth, or simply fuel the intransigence of the government? The intricate and sometimes testy verbal exchanges between Mr. Waldman and former CSIS director Ward Elcock on such issues as Canadian intelligence relationships with foreign agencies and knowledge of the use of torture abroad suggests how close to deadlock the inquiry might lurch.

Everyone involved in the Arar commission must be flexible if it is to be a success. The intelligence community will have to countenance the possibility of error and the need for institutional reform. The government will have to have more faith in the value of public knowledge in the national security arena.

There is much at stake in the Arar inquiry. The matter of justice for Mr. Arar is one consideration. There's the issue of public confidence in the state's national security practices. And intelligence services must prove capable of learning lessons from past mistakes, and make themselves truly accountable. At stake, too, is our cozy notion that the best way to get to the bottom of things is to turn them over to judges. I'd take a 9/11 commission any time.

Canada's post-election political realities should be a boon to the Arar commission. Any Liberal tendency to put a brake on the proceedings should be firmly resisted by the NDP.

As the commission proceeds, let's hope for an understanding that the only recipe for balancing national security and civil liberties in Canada lies in winning and sustaining public trust. Think of it as mending the democratic deficit on national security.

Wesley Wark, a historian at the University of Toronto, specializes in international security.