Every Democratic president and all Republican chiefs of state except Dwight D. Eisenhower have endorsed the treaty against genocide, written shortly after World War II. But conservative opposition for 35 years has blocked the US Senate from ratifying the pact.
Now the most conservative President in recent times, Ronald Reagan, may succeed in adding the United States to the list of 96 other nations that have signed. Only a week ago, shortly before he and Democratic presidential nominee Walter Mondale both addressed a B'nai B'rith meeting, President Reagan announced he was endorsing the treaty, which declares genocide an international crime.
Senate leaders are indicating that they want to speed the treaty on its way.
The Reagan endorsement came with only a few weeks left in an already-crowded legislative calendar, and it did little to counter longstanding criticisms of opponents. But with elections just around the corner, the President's announcement may have set the stage for ratification.
Sen. Charles H. Percy (R) of Illinois, chairman of the Senate Foreign Relations Committee, has scheduled a committee meeting for tomorrow to hear witnesses from the Reagan administration. After the testimony, the panel is expected to vote immediately to send the treaty to the Senate floor.
Senate majority leader Howard H. Baker Jr. (R) of Tennessee promised last week that he would give ''serious consideration'' to calling up the treaty. If he does bring it up for a vote, the only serious roadblock would be a filibuster or some other form of delay by opponents.
''I don't think this is one of these things they'll whip through in an hour or so one morning,'' predicted an aide to Sen. Jesse A. Helms (R) of North Carolina, one of the treaty's foes.
Mr. Helms and other opponents have long criticized the genocide treaty, which was drawn up as a response to the Nazi murder of millions of Jews, as a possible threat to American citizens. American bomber pilots during the Vietnam war might have been tried as international criminals under its provisions, according to the opponents.
Although the Senate Foreign Relations Committee drew up a list of reservations in 1974 which would be added to the treaty, opponents are not satisfied.
The critics also attack the treaty as meaningless. ''In the end, it may be a relatively innocuous document,'' says Jeffrey B. Gayner of the Heritage Foundation. ''At best it won't do any harm.'' But no supporter can point to any case in which genocide has been prevented, he asserts.
A US Department of State official responds to the charge that the treaty is just symbolism by saying, ''Take out the 'just.' In human rights matters, symbolism is important.''
The treaty's most steadfast friend in Congress, Sen. William Proxmire (D) of Wisconsin, defends it as ''a critical beginning of the end'' to the ''curse'' of hatred and mass killing. Almost every day the Senate is in session, Senator Proxmire takes the floor to speak for the genocide treaty. He has done so nearly 3,000 times.