This commentary by Prof. Ed Morgan was first published in The Globe and Mail on May 27, 2009.

Canadians may be surprised to learn a few things about our constitutional law.

First, the military owes no duty toward detainees arrested by us and turned over to a foreign state for custody.

Second, our intelligence service does owe a duty toward prisoners taken into custody by a foreign state and turned over to us for interrogation.

Third, our diplomats are obliged to intervene with a foreign legal system that fails to live up to our domestic standards of punishment.

And fourth, our police are free to comply with a foreign legal system that fails to live up to our domestic standards of search and seizure.

When it comes to the powers of the Canadian government abroad, each new court ruling makes us wonder if the judges took the time to read the last one. How did this confused state of affairs come to be?

In the latest case, the Supreme Court of Canada has refused to hear an appeal brought by Amnesty International on behalf of detainees in Afghanistan, confirming a lower court's view that the Canadian military is not restricted by the Charter of Rights and Freedoms when it operates in foreign terrain. The court saw Canadian Forces in Afghanistan as needing more leeway than the Charter allows in dealing with prisoners and in co-operating with our allies.

The point seems directly contrary to last year's Omar Khadr judgment, in which Canadian Security Intelligence Service interrogators in Guantanamo were held to the same standards as Canadian police when they investigate a crime at home. While the court pointed out that Mr. Khadr is a Canadian citizen and the Afghan detainees are not, that doesn't explain why intelligence officers should operate under a set of legal restraints that military officers are free to ignore. The Charter doesn't distinguish between citizen and non-citizen prisoners.

This year also saw the Federal Court of Canada pronounce that diplomats must lobby to support Ronald Smith, a Canadian murderer facing capital punishment in the United States. The ruling sidestepped international standards that give us the option, but not the obligation, to weigh in for a citizen in a foreign jail. Instead, it instructed us that the Charter of Rights has curtailed the government's discretion on whether to intervene in foreign legal proceedings.

The RCMP, by contrast, have no such worries. In the 2007 money-laundering case against Canadian businessman Lawrence Hape, the Supreme Court determined that the Mounties are free from the Charter's prohibition on unreasonable search and seizure when investigating a crime in the Cayman Islands. It's enough that they follow local police, who are at liberty to barge into a suspect's home without a warrant.

What explains this maze of legal contradiction? Everything and nothing.

When Canadian authorities operate abroad, the nation goes with them. From a legal point of view, there are two ways to look at it: They are either defending us collectively against enemies from without, or defending our values by spreading them far and wide.

For many, Canadian officers in Afghanistan or the Cayman Islands are protecting us from the harms of an adverse world. Whether for national security or crime control, Canadian authorities insulate the home front and represent our collective interest in keeping those hostile to us at bay. They have little to do with the Charter of Rights, which dictates how we treat each other, and everything to do with defending “We the People,” to use the U.S. constitutional phrase.

For others, Canadian authorities in Afghanistan or Guantanamo are enforcing the values of our rights-oriented society. Whether the campaign has a military or law-enforcement goal, Canadian officers are out to protect individuals everywhere against the impositions of the state, including themselves. They therefore travel with the Charter of Rights in tow, branching out our norms like a “living tree,” to use the British constitutional phrase.

We are a country with distinct national interests, and a society that values universal rights. There is nothing wrong with attempting to craft a body of law that reflects both sides of that coin. But it behooves our judiciary to at least try to rationalize its approach to the constitutional powers of government.

Litigation at this level ought not read like it was driven by the usual legal spin doctors, or by decision-makers who just go with their gut. If we faced our contradictions squarely, and tried to explain each ruling in terms of the last, we wouldn't just have a more comprehensible law; we would better understand ourselves.