As Gary Hart learned to his sorrow, presidential candidates are judged by the company they keep. Considering the scrutiny given all the 1988 hopefuls, Rep. Jack Kemp (R-N.Y)., the impeccably conservative candidate, may become an unwitting victim of association.

Kemp's anticommunist credentials are beyond reproach. But his ideological zeal has led him to champion a controversial group called the Anti-Bolshevik Bloc of Nations. Historians have linked some of its members to pro-Nazi organizations in Europe during World War II.

ABN leaders deny the charge. They claim that East European exiles among its members fought Soviet expansion, but not alongside Hitler's troops -- a claimed feat of logistics that leaves military historians dubious. ABN was formed at the conclusion of the war by exiles from a variety of East Bloc nations.

Heedless of possible embarrassment, Kemp has repeatedly voiced support for the anticommunist group. "You deserve our praise and admiration for promoting the cause of liberty for all those struggling under the burden of communist totalitarianism," Kemp wrote in a message read at the ABN's annual meeting last November.

Kemp may not have known about the background of some of the ABN delegates when he wrote this praise. For example, Ivan Docheff, a founder of the Anti-Bolshevik Bloc of Nations, was the wartime leader of the anticommunist Bulgarian National Legion. The legion has been described as "fascist" by the Bulgarian National Committee, an exile group based in Washington.

Docheff, who published a newspaper during the war that featured a swastika on its masthead, says he was a member of Bulgaria's anticommunist resistance, never a Nazi. "We resisted communist infiltration into our country," Docheff told Canadian journalist Howard Goldenthal last November.

According to Docheff, Bulgaria was never allied with Hitler in World War II. However, the fact is that Bulgaria declared war on Britain and the United States (though not the Soviet Union).

Docheff, who now lives in New York, said he has recently concentrated on helping elect Republicans to office. He has served on the GOP's ethnic- oriented Heritage Council, he said. The council's executive director, Radi Slavoff, said that Docheff had not been on the council in "many years" and was not "a positive element." Other ABN founders, including its late chairman, Yaroslav Stetsko, have been accused of collaboration with the Nazis against the Soviets in the Ukraine.

The Ukrainian Congress Committee, an exile group affiliated with various anticommunist groups here, denies that exiles like Stetsko had any Nazi connection. The congress claims that Hitler had Ukrainian nationalists imprisoned and that the SS secretly ordered their liquidation.

Upon Stetsko's death, Kemp paid a special tribute to him in the Congressional Record. A Kemp aide, Mary Brunette, told our associate Corky Johnson that the congressman supports the ABN goal of liberation from Soviet domination, but "certainly does not support anything that is anti-Semitic."