United Nations, N.Y. — After a quarter of a century, the shoe that a defiant Premier Nikita Khrushchev pounded on Moscow's United Nations desk personally and by proxy is on the other foot. In 1963, with his government a multimillion dollar delinquent in UN peacekeeping assessments, the Soviet ambassador said in a blistering speech that Moscow ``will not pay'' for peacekeeping operations in the Middle East and the Congo.
Today, it is the United States which, by withholding its assessed and voluntary contributions, has become what one Western diplomat called ``the UN's No. 1 deadbeat.''
At the same time, the Soviet Union is scoring political points with a dramatic turnabout in its attitude toward the UN.
Soviet leader Mikhail Gorbachev capsulized the new view when, during the recent Communist Party conference, he predicted that ``a universal system of international security will take shape, primarily through enhancing the role and effectiveness of the United Nations.''
Most UN delegates welcomed Moscow's avowed change of heart, specifically its pledge to settle its cumulative, multimillion-dollar peacekeeping debts and to play a more constructive role in the organization.
But across the political spectrum, the reaction was spiced with skepticism about Soviet intentions. Almost without exception, delegates said they would wait to see whether Moscow's performance matched its pronouncements.
In a recent interview, Herbert Okun, US deputy permanent representative to the UN, said: ``Pious generalities are nice to hear, but a healthy caution is in order.''
In a separate interview, Soviet Deputy Foreign Minister Vladimir Petrovsky spelled out what he called Moscow's ``new thinking with regard to the United Nations.''
``The USSR has just made a $25 million payment on its peacekeeping arrears,'' he said, and intends ``to cover the whole debt.'' In addition, he said, Moscow paid $38 million in April toward the regular budget.
One of the most dramatic Kremlin turnabouts was its insistence on strengthening the role of the Secretary-General. Traditionally, Moscow has resisted initiatives taken outside the Security Council, where it holds a veto.
But Mr. Gorbachev has said a Secretary-General is ``an authoritative figure enjoying everybody's trust,'' and that therefore ``all states should give him the maximum support.''
In assessing the new Soviet look, UN officials focused on its financial pledges as providing the most immediate benefits. Secretary-General Javier P'erez de Cu'ellar said that unless delinquent contributions are paid by the end of October or early November, ``the organization will be completely out of money'' and ``will have to cease operations.''
While figures vary widely depending on source, authoritative estimates put the total US debt for the regular budget and peacekeeping at nearly $532 million and the Soviet Union's at almost $230 million.
The US hopes to pay $188 million of its regular-budget arrears of almost $467 million this year. The Soviet Union has indicated it will pay off its $172 million peacekeeping debt within four or five years.
A senior UN official said the partial Soviet payment may induce other delinquents, including the United States, to follow suit.
The Russians are ``certainly more flexible'' and have unveiled a ``verbally creative policy,'' Mr. Okun conceded. ``But they still haven't put any clothes on the mannequin.''