Some hot spots -- and a hopeful note -- on US 'third border'

Here is a quick rundown on nations other than El Salvador that are the focus of new US attention: Guatemala: A neighbor of El Salvador, Guatemala has its own left-right face-off: a military government that leans right, leftist guerrillas who are bent on bringing down the government, and a long pattern of control of the many by the few.

But there is a viable middle class, particularly in the cities like Guatemala City, Antigua, and Quezaltenango, and this middle class could provide the basis for a broadening of economic benefits. At the same time, the government of Gen. Romeo Lucas Garcia does not appear sensitive to such considerations.

Many young people in Guatemala are demanding change. Their attitudes dovetail nicely into guerrilla strategy. It will take wisdom on the part of both Guatemalans and US representatives to alter this situation.

Nicaragua: The Sandinistas, who took power in July 1979, are facing woeful economic problems and are struggling to maintain some sort of balance between their natural friendship with Cuba, based on their mutual adoption of Marxism as their political and economic banner, and their desire for friendship with Washington.

They talk of a pluralistic political society and a mixed economy. But whether this proves practicable in the long run remains to be seen.

Most observers are beginning to doubt the viability of such an effort. Still the Sandinistas desperately need US aid. They are less likely to win a friendly ear in Washington now, however, for the Reagan administration asserts they have played a majorrole in supplying arms to guerrillas in El Salvador.

The verdict on Nicaragua's current movement is not in -- but the nation is having some trouble getting along with Washington.

Jamaica: From Washington's view, this island has provided perhaps the most hopeful sign in the whole region. The ouster of the Manley government by overwhelming popular vote in early November has brought to power a government that talks the same language as the Reagan administration. The Seaga government is capitalist oriented, democratically based, and friendly with the US. But its problems are horrendous. It desperately needs massive US public and private aid. The public aid -- to the tune of $40 million -- is on the way. The private aid may come. But Jamaica faces a difficult road as Mr. Seaga tries to restore a shattered economy based largely on bauxite and tourism -- and the illegal trade in marijuana.

Happily the sun shines brightly and the island having its best winter tourist season in a decade. But now Mr. Seaga has to get down to the hard business of restoring economic health in a time of high inflation, high prices for oil, and other problems. And he must grapple with the moral implications involved in half the island's trade receipts coming from the illegal "ganja," or marijuana trade with the US.

Puerto Rico: A wholly different set of problems, without the sharp edges of guerrilla and terrorist violence like that in El Salvador or the economic sluggishness of Jamaica, bedevils this island. It belongs to the US in a loose arrangement called a commonwealth and has much more freedom than many states.

Many islanders want statehood, but others want independence, and still others want to keep the free state arrangement. Either way, decisions on which direction the island will go are likely to have to be made during the 1980s, and Washington will have to adjust to these new realities.

Cuba: No other country is so central to the whole problem facing the region. Fidel Castro has implanted a strong Marxist political and economic system on the island that is anathema to the US and also to many in Cuba. Yet Dr. Castro continues to enjoy wide support among his people.

He admits, however, that his island's economy is not doing well. Sugar, on which foreign trade is based, has had several bad crop years because of bad weather and blight. Tobacco has also suffered, and the rest of the economy has not been good, either.

Castro says that much of his island's trouble stems from the US economic blockade of the island. He said only this month that the blockade must end. He has also spoken in recent weeks of his desire to improve ties with Washington.

Nonetheless Dr. Castro remains committed to allegiance to the Soviet Union and to the expansion of his island's influence throughout the Americas -- points that Washington cannot accept. Aid given to El Salvador's guerrillas is the obvious example. Cuba may deny that it is providing such aid, but Washington is determined to prove it has been doing just that.

How the Reagan administration handles Cuba and the other problems of the area will obviou sly affect the future direction of these countries.