My guess is that the politicians in Washington who are getting themselves on record as being against President Reagan's Central American venture are someday going to regret it.
My reason for thinking this is that there are two enormously important differences between Vietnam and Central America. One difference is population. The other is location.
Vietnam has a population of 90 million. Cuba has 10 million, Nicaragua has 2. 5 million, El Salvador has 5 million. Thus if El Salvador went Marxist and joined up with Cuba and Nicaragua the combined population would still be only about a fifth of the population of Vietnam.
Vietnam is located on the far side of the world from the United States, but next door to China, the world's most populous country which, at the time of the US involvement in Vietnam was aiding Vietnam because it did not want large US military forces on the mainland of Asia and within easy striking distance of China's southern border.
Vietnam is also down the Asian coast from the Soviet Union's maritime provinces.
It was easy, and relatively cheap, for China and the Soviet Union to send supplies of all kinds, including weapons, into Vietnam. During most of the war the port of Haiphong was wide open and untouched by US bombs or blockades. After it was bombed the Soviets unloaded their cargoes through smaller ports, or over the beaches. Chinese supplies came down the road network from China, untouched by US bombs.
The weapons which moved from China and the Soviet Union went to a people in Vietnam motivated by a vigorous nationalism who easily fielded an army which substantially outnumbered the forces which Washington was politically able to send that far overseas.
The military situation in Vietnam was so unfavorable to the US venture that the veterans of the Korean war, including former chiefs of staff Matthew Ridgway and Joseph L. Collins (who were sent to Vietnam to report on the military situation) advised against it.
The earlier Korean venture had persuaded much of the top level of the Pentagon that the US would be making a grave mistake to get itself involved again in a major war on the mainland of Asia. President Lyndon B. Johnson ignored the advice of the top veteran generals of the American army.
Central America presents a reverse military situation.
According to public opinion polls, Mr. Reagan's Central American venture is unpopular. There is obviously no great enthusiasm for it. There is firm popular opposition based, presumably, on the fear that Central America could turn into another Vietnam.
But the plain fact is that it cannot turn into another Vietnam. There is no way that Cuba, Nicaragua, and the rebels in El Salvador could join together to present a force in any way comparable to the large and highly motivated forces of Vietnam.
Yes, Cuba has a respectable army of a quarter million men. It has shown fighting capability. It could probably put up a vigorous defense against an attempted invasion of Cuba.
But President Reagan does not need to invade Cuba to win the hand in Nicaragua and El Salvador. All he has to do is move a small part of US sea power into the area. He can, if he chooses, use that sea power to halt all traffic between Cuba and Central America. And he can use that sea power to prevent help from any other source reaching Nicaragua and the rebels in El Salvador.
The Soviet Union is in theory a factor in the equation. But the Soviet Union is 6,000 miles away. And the Soviet Union has just signed a deal with the US to increase its purchases of US grain by 50 percent. It will be buying at least 9 million metric tons tof US grain each year for the next five years.
This is about as clear a signal as there could be from Moscow to its clients in Central America that they are on their own and need expect little more than money and sympathy if they decide to tangle with President Reagan. The Soviets are no more likely to get into a confrontation with the US over El Salvador than the US is to get into a confrontation over Poland.
Protests and perhaps economic sanctions might be used. Washington and Moscow are both quick with gestures, but slow with real force, when the action is in the other's front yard.
The likely outcome of all this is that the government in Nicaragua will decide that wisdom is the better part of valor and come to terms with Mr. Reagan - including an end to the rebellion in El Salvador. In that case Mr. Reagan will get the political credit for winning without ever sending US forces into combat.