In Europe last week one man was declared guilty and one man innocent for ''crimes'' committed more than 40 years ago. Klaus Barbie, SS chief in Lyon during the Nazi occupation of France, was found guilty of ''crimes against humanity'' and sentenced to life imprisonment. Theodor Raskolnikoff, a Soviet diplomat who denounced Stalin's crimes, was posthumously and informally ''rehabilitated'' in a Soviet publication for the letter he wrote denouncing Stalin in August 1939.

Both cases raise fundamental questions about the relation of citizens to their governments. What are the limits of a citizen's obligation to his government? When can obedience to a brutal government be judged a crime? These are, of course, questions encountered again and again in history and in political philosophy. They are the questions of Socrates, Antigone, Martin Luther and the men who signed the American Declaration of Independence. They are relevant not only to the past. They are urgent questions in confronting current horrors.

Nazis like Klaus Barbie and Adolf Eichmann claimed that not only were they obeying orders from their government, but that their obligation to obedience had no limits. Their prosecutors -- at Nuremberg, in Jerusalem, in Lyon and wherever Nazis are tried for such crimes -- argue that there are some things no government has the right to require and some things every citizen has the obligation to refuse: the cold-blooded murder of civilians, the elimination of ''inferior'' races. Such acts cannot be excused or justified -- not during wartime or by oaths of obedience. A citizen is neither obliged nor permitted to commit ''crimes against humanity.''

But is a citizen permitted to protest massive violations of human rights by his government? Governments that claim total power over their citizens don't think so and, except for the brief ''Moscow spring'' of Nikita Khrushchev's ''de-Stalinization'' period, the Soviet government has considered it a crime to criticize its human rights violations.

Theodor Raskolnikoff knew this and sought refuge in France at the same time he released his open letter to Stalin on Aug. 17, 1939. After years of dishonor, Raskolnikoff was ''rehabilitated'' by Khrushchev only to be again denounced for Trotskyism and treason under Brezhnev, and now to be once again informally ''rehabilitated.''

These two events have interesting implications. Does Klaus Barbie's reclassification from Nazi official to French criminal mean that it is all relative, that law and morality are merely a function of power, that -- as Socrates' antagonist Thrasymachus of Chalcedon argued -- justice is merely the interest of the stronger?

No. It means that the Nazi regime was vicious precisely because it did not respect the human rights that Klaus Barbie was found guilty of violating.

Does Raskolnikoff's ''rehabilitation'' mean that the Soviet government is now willing to accept limits to its power and to accept that its citizens have the right to criticize government excesses? Does it mean that the Soviet Union is now ready to respect the human rights of its citizens in theory as well as in practice?

Not necessarily. Raskolnikoff, like Boris Pasternak (also again being mentioned in the Soviet press), is long dead. So is Joseph Stalin. The right of a long-dead man to criticize a long-dead ruler is hardly the equivalent of the right of living persons to criticize incumbent power-holders. Last week a living Soviet, Anatoly Koriagin, was stripped of his Soviet citizenship for criticizing the use of mental hospitals and mind-altering drugs to punish dissidents.

When current Soviet rulers permit living citizens to criticize today's leaders and policies, then we will know that they share what French Prime Minister Jacques Chirac described last week as the core values of democratic Europe: ''a certain idea of liberty, of democracy and of the rights of man.''

Everything is easier to face 40 years later. Terrible as it is to hear Barbie's victims describe his crimes, how much more difficult it is to think about such terrible contemporary ''crimes against humanity'' as Ethiopia's ''village-ization,'' described recently in The New Republic:

''The basic outlines of the program are not in dispute. The army moves into a group of villages, and forces the inhabitants to tear down their huts piece by piece. Then the peasants are force-marched, with the remnants of their homes on their backs, to a new, central location previously selected by party cadres. The new site usually lacks a mosque, a school and an adequate nearby water source, but it comes equipped with a guard tower and Workers Party banners.

''By the end of 1986 close to 4 million Muslim Oromos . . . had been forcibly uprooted through this nightmarish scheme. And 29 million others are slated for the same fate by the mid-1990s.''

When will someone, somewhere, try Ethiopian Col. Mengistu Haile Mariam for his ''crimes against humanity''?