A LITTLE-NOTICED provision of a bill soon to be taken up by a key House committee threatens to make a big dent in United Nations peacekeeping operations around the world, according to congressional sources and worried Clinton administration officials.
The provision, contained in draft legislation that is part of the GOP's ''Contract With America,'' would require the UN to reimburse the United States for military support it provides to UN peacekeepers and for the cost of American peacekeeping missions. This includes operations like the one now under way in Haiti, which the United States operates with the blessing, but not the participation, of the UN.
If the cash-strapped world body fails to reimburse the US, according to the draft law, the US would deduct such costs from its assessed annual share of the UN peacekeeping budget -- a measure that would have severe effects on UN peacekeeping, critics predict.
''It's a complicated provision that few people really understand,'' says one congressional source of the draft measure. ''But it could effectively destroy the concept of collective security.''
''It may not wreck collective security, but it means that the cash flow for UN peacekeeping could dry up totally,'' adds Douglas Bennet, assistant secretary of state for international organizations.
If enacted, the National Security Revitalization Act would make mandatory what has been voluntary since 1988, when the UN agreed to reimburse the US for some of the costs incurred in providing logistical support for a UN peacekeeping mission in Namibia.
Since then, United Nations reimbursements to the US have steadily increased.
A similar ''charge-back'' provision is contained in a draft ''peace powers act'' sponsored by Senate majority leader Bob Dole (R) of Kansas.
''Clinton has a world view that the US can't function without the UN,'' says a Senate Foreign Relations Committee source. ''This makes it clear that the UN can't function without the US.''
Besides its regular annual UN dues (about $300 million), the US now pays 31 percent of the UN's annual peacekeeping budget of nearly $4 billion, an assessment that will be reduced to 25 percent starting Oct. 1.
In addition, the US shoulders indirect costs by providing logistical and other military support to some of the 17 UN peacekeeping missions now deployed around the world, including those in the former Yugoslavia, Cyprus, and Somalia.
The US also bears the cost of its own peacekeeping missions, such as the US force now maintaining order in Haiti.
GOP lawmakers say the reimbursement provision is needed to help sustain the Pentagon's ''operations and maintenance'' budget, which is the source of money needed to keep US forces at peak readiness.
Opponents of the measure say the readiness issue is misleading since the direct and indirect military support the US provides the UN is helping to protect America's own security interests.
''Gingrich says we're spending millions of dollars aiding UN operations but not getting reimbursed,'' says Ralph Cwerman, vice president of the United Nations Association of the US, in New York. ''What everybody forgets is that these operations were set up and approved by the US and the other members of the [UN] Security Council.
''If you don't provide adequate resources for the UN to do the job, the job won't get done, and the job has a lot to do with US's own national interests,'' Mr. Cwerman says.
If last year is any indication, the new law could bankrupt the UN peacekeeping budget. The Pentagon spent $1.7 billion on UN peacekeeping and humanitarian operations, most of which was not reimbursed by the UN, according to figures cited in the draft legislation. By comparison, the US's assessed share of the UN peacekeeping budget was only $1.2 billion.
If the proposed law had been on the books in 1994, the US contribution to UN peacekeeping would have been wiped out and the $500 million balance would have been owed by the UN to the US, according to GOP sources.
Critics of the proposed law say it could set a precedent for other nations that, like the US in Haiti, have mounted independent but UN-approved peacekeeping operations.
''If we were to pass this, what do you think the Russians would say about paying for peacekeeping in Georgia or Tajikistan?'' asks the congressional source. ''And the French would say, we've spent billions of our own money helping to save Rwanda, and we need to be paid back, too.''
''This all looks technical, but the bottom line is that it could destroy peacekeeping,'' says the congressional source. ''Basically, we're saying we're going to play by different rules than anyone else.''
The payback provision is similar to one offered by then-GOP minority leader Newt Gingrich (R) of Georgia that was voted down in the House last year. With the GOP now in control, the measure is expected to pass.
The House International Relations Committee is scheduled to hear testimony on the bill from Secretary of State Warren Christopher this week. It then plans to bring the measure to a quick committee vote.
The National Security Revitalization Act contains other provisions that would limit US participation in UN peacekeeping by restricting finances, forbidding foreign command of US troops, and requiring more congressional oversight.