BY USING one of the votes on the IMF to needle some Democrats, the National Republican Congressional Committee has thrown the bill into greater jeopardy than ever. But it's President Reagan's bill.

The Republican Congressional Committee, which is not known for thinking deeply about these things, is using the bill to try to label the Democrats supporters of communism and so forth. As a tactic it lacks imagination and, fortunately, it also lacks the destructive power that it once had. But that kind of charge can still irritate people mightily--people whose votes the president needs if he is to get the bill enacted. Where were the White House people who are supposed to be watching over the bill? On vacation, apparently. From the beginning, the administration has botched the management of this bill, chiefly through this kind of inattention.

The incident revolves around an amendment that Rep. Phil Gramm succeeded in attaching to the bill, requiring the U.S. representative to the International Monetary Fund to vote against loans to any countries under "communist dictatorships." Most sensible people opposed it, including the Republican floor leader, Robert H. Michel, and a good many other prominent Republicans as well as Democrats. But the Republican Congressional Committee saw an opportunity, of sorts, and has been mailing literature into some of the Democrats' districts asserting that they "voted . . . to loan U.S. taxpayers' money to communist nations."

The IMF's job is to stabilize the world's monetary system and support trade. Ever since 1947 and the Marshall Plan, the United States has tried to draw at least some of Eastern Europe into the world trading system. Over the past decade things have been moving slowly in that direction, and among the Warsaw Bloc countries, Hungary and Rumania are now members of the IMF.

A question for Mr. Gramm and his admirers at the Republican Congressional Committee: would the world be a better place if the West refused to deal with Hungary and Rumania and forced them into total reliance on the Soviet Union? Another question: would it serve American interests if the IMF refused the loan to Yugoslavia and forced it into bankruptcy?

The purpose of the bill is to increase the IMF's lending authority, and it's urgently needed. The effect of the assault by the Republican Congressional Committee is to make it more difficult for the Democratic leadership in the House to find votes for Mr. Reagan. The bill's floor manager, Fernand J. St Germain, has now revived his demand that, in return for further help on the IMF bill, the president must support the excessively large housing bill stuck in the Senate. The chances for the IMF legislation are not improving.