The Soviet Union's senseless destruction of a civilian South Korean airliner with the loss of 269 lives will have foreign-policy ramifications for years to come, many of which have yet to surface.

But one thing is crystal clear: That indefensible act will make it even more difficult to get appropriations through Congress for the International Monetary Fund and for some of the multilateral development banks that--in the view of many congressional right-wingers--already are playing footsie with the Communist bloc.

It is doubtful that Congress will have approved the IMF legislation by the time of the IMF and World Bank hold their annual meetings here in two weeks. In fact, an angry debate over the bill could coincide with the annual meetings, and prove highly embarrassing to the Reagan administration.

Congress' latest beef with the IMF is that it made a $14 million loan on Aug. 14 to Grenada, which has a Socialist regime with links to Cuba and the Soviet Union.

Even before the Korean plane incident, the Reagan administration had agreed--in its desperate effort to get the $8.4 billion IMF authorization bill passed--that, in the future, the American executive director for the IMF would oppose loans to Communist countries. (The United States also would be enjoined to oppose loans to South Africa, in response to apartheid.)

American opposition in such cases would not prevent such loans from going forward if a majority of other countries approved.

But because the margin of approval for the IMF authorization in the House was only six votes, it is possible that, when a vote on the Senate-House conference version comes up, the new anti-Soviet mood could kill the IMF bill altogether.

At the end of June, in a situation where it could exercise a veto, the United States blocked the Inter-American Development Bank from extending $2.2 million of a larger loan to Nicaragua, and early in August banned a $10 million loan to Guyana. The reason: The United States said it doesn't like the macroeconomic policies of those two socialist governments.

With attention focused on the administration's desperate attempt to rescue the $8.4 billion IMF bill from an obviously reluctant Congress, the equally difficult financing problems of the World Bank have been shoved into the background.

But discontent with the IMF and other multinational banks spills over to the World Bank, whose president, A.W. Clausen, is confronted with a seemingly rigid U.S. Treasury belief that it lends too much money to countries--notably China and India--that ought to be borrowing from private commercial markets instead.

Treasury Secretary Donald T. Regan says flatly that there is no sense in asking Congress to appropriate more than $750 million a year for the International Development Association, which makes 40-year, no-interest loans (with a small service charge) to the poorest of the poor countries.

Regan and Undersecretary Beryl Sprinkel insist that IDA can and should get along with $9 billion for the next three years, instead of the $16 billion that Clausen says is the rock-bottom total needed. In effect, that would represent a cut of about 25 percent from the original U.S. commitment for the IDA program now winding up--a slash, that is, from the promise outlined at the end of the Carter administration and stretched out by the Reagan administration and Congress.

Clausen says that, with China now a major client for the IDA, and taking into account inflation over the past few years, a $9 billion limit will cause untold hardship in the Third World. But Sprinkel told this reporter in a recent interview that, while the United States supports the basic programs of the World Bank, it believes the bank should be pulling in its horns somewhat.

"We are trying very hard to focus on improving the quality of some of the loans at the World Bank . . . " Sprinkel said.

"We do not believe that quantity of loans is the only, or perhaps even the major, contributor to economic progress and growth and development. Some tend to measure your concerns about poor countries by how much money you're willing to put into the IDA. We think there are many other factors that determine growth over and above subsidized funds. And that certainly includes the kinds of economic policies that the recipient nations pursue. If they do not encourage savings and investment and incentives in their own country, pumping in subsidized money will not buy them much except a temporary respite."

Clausen says repeatedly that it's wrong to "politicize" the activities of his and other multilateral-lending banks. He affirms repeatedly that the only ideology the bank pays attention to is pragmatic economics.

"I would hope, Mr. Rowen, that you would put in your article that there needs to be a broader understanding of the self-interest of the United States," Clausen said in an interview. "That 40 percent of the exports of goods and services for the United States goes to Third World countries, and by helping Third World countries expand their economies, it means more jobs at home. It means a stronger trade position, a stronger balance of payments."

Clausen makes sense. But he and the rest of the international financial community will be scarred by the missile from the Russian Su15 fired at Korean Air Lines flight 007.