IT is one of the oldest questions in American foreign policy: whether isolating or engaging dictatorships is the best way to bring them down.
For 30 years, the United States has opted for isolation in dealing with the dictator in its own neighborhood, Cuba's Fidel Castro Ruz. Now, some of President Clinton's senior advisers as well as leading conservatives are taking issue with a policy that has so far failed to budge the longest-ruling leader in the Western Hemisphere.
``In the post-cold-war era, the only policy that makes sense is aggressive engagement,'' says Gary Jarmin, chairman of the US-Cuba Foundation, an association of conservative Republicans who support lifting the embargo and normalizing relations with Cuba. ``If we try to isolate Cuba, it will only result in higher immigration, lost business opportunities, and a possible military confrontation with Cuba.''
Successive US presidents have enforced a trade embargo that was imposed on Cuba in 1962. The consensus for isolating Cuba held through the end of the cold war, when it appeared Castro would go the way of other communist leaders.
In the five years since, however, the Cuban leader has managed to weather severe crises, including the cutoff of huge Soviet subsidies and a 50-percent shrinkage in the island-nation's economy. With its economy on the upswing again, foreign-policy experts from both parties say new tactics are needed to force Castro to relinquish power or make political and economic reforms.
The issue was joined on Tuesday when news leaked that the Clinton administration was contemplating lifting two sanctions - tighter travel restrictions and a ban on individual remittances to Cuba from the US - that were imposed to stem a Cuban boat exodus last August.
Administration officials insist that no thought is being given to lifting the 33-year US trade embargo on Cuba, but they add privately that it might be time to test Castro's willingness to make concessions.
Word of possible backsliding by the administration galvanized Senate Republican leaders, who rallied behind a move by Senate Foreign Relations Committee chairman Jesse Helms (R) of North Carolina to attach an amendment to a Pentagon spending bill to maintain existing travel and trade sanctions.
The effort was dropped late Wednesday, but Mr. Helms plans to hold hearings next month on legislation that would tighten sanctions on Cuba further - a move he says would administer the coup de grace to Castro's tottering regime.
``Why should we let up the pressure now?'' Helms asked reporters when he unveiled the bill last month. ``It's time to tighten the screws.''
The Helms legislation, among other things, would prohibit sugar imports from countries that import sugar from Cuba and urge the president to seek a UN embargo against Castro.
But other Republican luminaries, ranging from conservative columnist William F. Buckley Jr. to former Reagan administration officials, say this is the wrong way to deal with Cuba's aging leader.
``The reason why the policy of tightening the screws won't work is that when the going gets tough in Cuba the tough go rafting,'' says Mr. Jarmin, referring to boat people who have fled Cuba. ``All that does is exacerbate the immigration problem.''
Lifting the embargo, on the other hand, ``would be the most destabilizing thing that could happen in Cuba,'' Jarmin adds.
Opposition to tighter sanctions is echoed by US business leaders who are eager to cash in on an opening market and who argue that commerce, not coercion, is the key to change in Cuba.
Though some US companies can now operate on a limited basis in Cuba, most are closed out of what US firms see as a lucrative market - especially in mining, telecommunications, tourism, and pharmaceuticals - that is being taken over by non-US investors.
``Investments from countries like Mexico, Spain, Canada, and Germany are growing at an exponential rate,'' says John Kavulich, president of the US-Cuba Trade and Economic Council, a nonpartisan business group based in New York.
``For every day the US business community is precluded from Cuba, it will take a year to catch up with overseas competitors,'' Mr. Kavulich adds.
``That's what I hear from some of the largest companies in the US.''
Last year, more than 250 executives and representatives of US businesses traveled to Cuba to scout out investment opportunities. According to the US-Cuba trade council, Cuba is more familiar with US products than is any other non-English speaking country.
``You've got 12 million people who know the names Snickers, Coca-Cola, and Ford,'' says Kavulich. ``That's pretty attractive.''
The US is the only country that maintains an embargo on Cuba. One reason is the strong lobby that represents the nation's 1.5 million Cuban-Americans - which also accounts for the fact that most of the opposition to easing sanctions is voiced by people who are not currently holding elective office.
``There's influential opposition to maintaining sanctions,'' says Peter Hakim, president of the Inter-American Dialogue, a private research group in Washington. ``But it still doesn't make much difference where it counts, which is on the Hill or in the executive branch.''