ON MAY 7 OF this year, Yuri Zakharenko disappeared. Viktor Gonchar disappeared on Sept. 16. So did Anatoly Krasovki. All three were political opponents of the reigning dictator of their country, Belarus. None has been seen or heard from since. Their disappearances--along with the imprisonment of many other opponents--are reminders that strongman Alexander Lukashenko is not the unsavory but essentially harmless buffoon he is sometimes taken for. On the contrary, he is a dangerous descendant of Joseph Stalin. The United States should be concerned, and not just on behalf of the 10.5 million oppressed and impoverished people of Belarus.

President Clinton is in Istanbul this week for a conference of leaders that, at one time, might have been cast as a celebration. The conference organizer, the Organization for Security and Cooperation in Europe, fought for human rights behind the Iron Curtain; that divider is long gone. The term "dissident" ought to have become quaint by now.

But in the Slavic heart of the old Soviet Union, there isn't much to celebrate, and Mr. Clinton and his fellow leaders shouldn't pretend otherwise. Russia is waging a brutal war against the people of Chechnya. Ukraine's President Leonid Kuchma just won reelection in a contest that was decidedly less fair and democratic than previous ones.

And in Belarus, any supporter of democracy becomes automatically a dissident and every dissident is in danger from authorities. "Who will be next?" asks one of the brave ones, Anatol Lebedko. "Sometimes we feel safer in jail than out on the streets." Mr. Lebedko, recently freed from a 10-day imprisonment for his role in organizing a protest rally, notes that Mr. Lukashenko's brand of totalitarianism is a kind of "export commodity"; nostalgic Communists and neo-fascists in Russia, Ukraine and elsewhere look to him as a model. Just as during the Cold War, Mr. Clinton and his fellow OSCE leaders in Istanbul must make clear where they stand: with the victims of Russian force and Belarusian oppression, or with the oppressors.