One thing is sure. If the Reagan administration does obtain agreements in expected new talks with Nicaragua and Cuba, they will have a special credibility.
No one could accuse this administration of being soft on communism, anymore than the Nixon administration could be so accused when it renewed relations with China. Though Central America and the Caribbean represent a far smaller diplomatic scale, their nearness to the US makes the credibility factor particularly important. And this factor would not only work to gain support for any resulting agreements in the US. It would also work to ratify Cuba and Nicaragua, like China, as capable of peaceful international relations despite their various degrees of dubious internal rule.
Thus there was encouragement in the renewed focus on conciliation last week even as President Reagan was taking the occasion of his Caribbean trip to lambaste the leftists, including tiny Grenada, once again.
Nicaragua came to the fore as the US offered the Sandinista regime an eight-point proposal for reducing tensions between the two countries. Nicaragua's first response was not to the plan itself but to the ''positive'' gesture of US willingness to talk.
It was ''like saying hello,'' said a Nicaraguan official in Washington, with more informal talks likely before the formal negotiations agreed to through Mexico's good offices last month.
Most of the eight points were ones the US had previously mentioned, including a pledge by Nicaragua not to support insurgents in other countries such as El Salvador; a pledge by the US to forbid anti-Sandinista groups to launch military action from the US; and a mutual pledge of noninterference in each other's countries. The latter point gains fresh weight in the light of reports the US is underwriting plans for covert action against Nicaragua.
One point stressed by the US State Department as an inducement to Nicaragua is a more explicit statement than before on resuming direct aid to Nicaragua as well as including it in Washington's Caribbean Basin plan if relations between the countries are restored. At the same time international verification of observance of the agreement is called for. So is Nicaraguan assurance of proceeding toward political pluralism.
Though Nicaragua has stuck at some of these points before, the time is ripe for it now to reconsider - or to present counterproposals. After the US's ''hello,'' it would be sad to have any more goodbyes before agreement is reached.
Similarly the time is ripe, or beginning to be ripe, for talks with Cuba. Secret meetings between US and Cuban officials have already taken place. Both governments expect further discussions, though no dates have been arrived at.
What might give some impetus to the process is a reported Cuban willingness to go into matters such as arms for El Salvador's guerrillas and multilateral foreign policy questions. The US has doubted that there is any give on the Cuban side.
Earlier this month a high Cuban official told a group of visiting US scholars that Cuba had indeed shipped or transshipped arms in the past but that it was no longer doing so. The official also distanced Cuba from Soviet policy in some ways and said Cuba was willing to discuss foreign policy with the US in a multilateral context. And such discussions could be without the diplomatic normalization, such as prior lifting of the US trade embargo, that has been demanded in the past.
Many of those present considered the remarks a serious effort at nudging conciliation along. Maybe it was a kind of ''hello'' by Cuba on which the Reagan administration could start to build sound future relations.