The United States cannot easily return to the high-profile mediating role it played before war broke out on the Falkland Islands. But experts say it can now play a key, albeit low-profile, role in the search for a lasting settlement.
President Reagan left the option of US assistance open in a three-sentence statement issued by the White House on June 15.
''For its part, the United States continues to stand ready to assist in any way it can to help resolve this conflict,'' the President said.
As some Latin America experts here see it, the problem comes down to encouraging Britain to accept a settlement which does not exclude Argentina from an eventual role in dealing with the islands. The US wants both to avoid further humiliation of the Argentines and to begin to ease the tensions which were created between the US and a number of Latin American nations as a result of American support for Britain.
For the moment, however, there are limits on how much the US can do. Secretary of State Alexander M. Haig Jr. met on June 15 to discuss the issues with Nicholas Henderson, the British ambassador here. But a State Department official said it was ''too early to say'' what the US role might be in arriving at a permanent solution to the conflict.
State Department officials are not enthusiastic about suggestions, some of them coming from Britain, that the US join a multinational peace-keeping force for the Falklands. For one thing, the US is not certain what Argentine feelings about such a move would be. And the US does not want to appear in Latin American eyes to be supporting what some Latins consider to be a perpetuation of colonial-style British rule.
Riordan Roett, director of Latin American Studies at the School of Advanced International Studies at Johns Hopkins University, thinks there are, nonetheless , a number of things which the US can do to mend relations with Argentine and facilitate a lasting settlement.
''First and foremost, I think it important that we not step back from our very firm support of the British position . . . against the use of force to settle territorial disputes,'' said Mr. Roett.
''Second, now that that issue has been ended, and Great Britain has retaken its territory and has reasserted its sovereignty, we also need to stand very firm . . . and explain to the British that the United States - and indirectly Great Britain - have long-range interests in resolving the issue of the Falklands politically.
''That means either moving toward some form of international administration, moving toward arbitration or mediation, and ultimately, and this need not be said publicly at this moment, but ultimately moving toward Argentine sovereignty over the Falklands.''
When it come to US-Argentine relations, Roett suggests the US encourage private investment in Argentina and help to ease the burden of Argentina's massive international debts by playing a ''positive role'' on behalf of Argentina in international lending agencies.
Roett does not think that -- with the exception of Argentina -- much permanent damage has been done to Washington's relations with Latin American nations. He thinks the US should encourage nations which have been relatively neutral in the Falklands conflict -- such as Brazil, Colombia, and Mexico -- to help set up an administration and multi-national peace-keeping force for the Falklands.