The modern Turkish Republic, successor to the Ottoman Empire within shrunken borders, is the only Muslim country in the Middle East that maintains a functioning democracy. Turkey borders Iran, Iraq, Syria and Russia. Passing a self-serving resolution condemning Turks for horrific things that occurred 90 years ago would alienate an important ally without achieving anything of substance for the United States. An American rebuff, added to recent European actions hostile to Turkey, would only strengthen malign anti-Western Islamist and nationalist minorities in Turkey.

Armenians contend 1.5 million or more people were systematically killed between 1915 and 1923. Turks say a far smaller number of people died, not by deliberate extermination, but as a consequence of a brutal war in which Armenians were deported because they sided militarily with invading Russians. There is no doubt that large numbers of Armenians suffered terrible deaths and deportations; Muslim civilians were also ravaged.

The weight of opinion outside Turkey has favored Armenian claims. But Chris Morris, British author of The New Turkey, says: ''Both sides produce stacks of documents to back up their arguments . . .'' Respected historian Guenter Lewy concludes, ''The primary intent of the [Ottoman] deportation order was undoubtedly not to eradicate an entire people but to deny support for the Armenian guerrilla bands and to remove Armenians from war zones.'' The tragic consequences for Armenian civilians should be remembered. But politicians have no qualifications to judge Ottoman intentions nine decades ago.

Similar congressional resolutions have failed to pass in recent years. The reason the current resolution is being pushed by more than 160 House co-sponsors is that the November elections empowered California Democrats, and there are many Armenian Americans residing in California and elsewhere who are actively lobbying. They deserve respect for keeping alive the memory of what happened to their ancestors, but not at the price of rupturing relations with a key American ally.

Turkish Americans are too few to lobby effectively. Speaker Nancy Pelosi, ignoring concerns persuasive to prior House leadership, has scheduled a rushed vote for this month. Pelosi should ask the Department of Defense what would happen if Turkey curtailed co-operation with U.S. forces in the Middle East and Afghanistan.

There is much Turkey can do to prevent congressional resolutions from becoming a perennial irritant, e.g., tempering anti-American propaganda in media close to the ruling AKP party and increasing protection of human rights. Turkey is not improving its image by cozying up to Hamas terrorists.

But passage of this resolution would inflict a major foreign policy disaster on America by rupturing relations with a country vital to execution of our foreign policy.