THE AIR in Washington fairly crackles with patriotic expectation for the war in El Salvador but the American people are in urgent need of education on that tiny cockpit of democracy. Why is the Twinkie-shaped republic of El Salvador so important to American freedom? And, for that matter, where exactly is El Salvador? When the first casualties came back from the last freedom fight in Indochina, some parents didn't even know where their sons had been killed.

The most reassuring point being emphaiszed by high administration sources, including the president, is that El Salvador is not Vietnam. This is important to keep in mind because the usual hysterical voices will no doubt make glib comparisons between the two. Be assured: There's no Big Muddy in the Little El.

For one thing, it's too small. El Salvador, according to the best-informed foreign correspondents, is the size of Massachusetts. This is stated authoritatively in the World Almanac. Vietnam, on the other hand, is the size of New Mexico. Pentagon strategic planners are fully cognizant that fighting a land war in New Mexico is not the same as standing off a handful of disorganized Marxist-Leninist guerillas in Massachusetts. No way we can squeeze 500,000 U. S. troops into El Salvador.

Think of the Cold War like college basketball and Vietnamn and El Salvador as a home-and-home series with the Reds. This time, the U.S.A. has the home-court advantage. In diplomacy, this is known as the Monroe Doctrine. The basic coaching strategy seems to be: pick up a quick win in Central America, rebuild team confidence, then take them on the road, maybe to Africa.

But we are also sending messages, which is one of the best things about little wars. Nobody cares that much about El Salvador real estate, but it's a great way to caveat Moscow and Cuba ("lay off our countries") and also weak-spined allies in Europe ("stick with the Duke, fellas, 'cause he's a winner").

Sometimes, the messages get garbled. For instance, President Reagan just got through telling Mexico that Mexico is our favorite country in the neighborhood. Then Mexico turns around and declares that its favorite country is Cuba. But everyone knows Cuba is our favorite enemy. In diplomacy, this is called "triangularization."

Our embattled ally is bordered by Guatemala, which is the size of Ohio, and Honduras, which is the size of Tennessee. But the real trouble comes from Nicaragua, which is almost as big as Florida. From Nicaragua, Red arms and ammunition are smuggled across the Golfo de Fonseca, which is almost as wide as the lower Chesapeake Bay, and into the hands of the Marxist-Leninist guerrillas.

El Salvador is on the Pacific, not the Caribbean. It has a hot coastal plain and, according to a reliable old Esso map, good beaches. Most of the people live on the cooler plateau. In the mountains, there are several volcanoes, which have no strategic importance.

The population (about the same as Maryland's) is 89 percent Mestizos -- of mixed Indian and Spanish heritage. They speak Spanish and go to Christian churches, which provides an immediate cultural linkage never fully developed in Indochina. One Pentagon option paper proposes that the4 U.S. expeditionary troops be made up of Spanish-speaking Americans. No doubt, this could simplify any draft problems. We could draw soldiers entirely from Florida, Texas, California and East Harlem, where everyone knows Spanish.

El Salvador does have a minor minority group composed of Indians who speak only Nahuati. However, since the unassimilated Indians are generally hostile to Spanish-speaking Salvadorans (Sallies ) of both left and right, they may welcome the American presence as a "third force" that could organize them into separate fighting units, as fierce as Meo tribesmen.

The capital city of San Slvador, is precisely the size of Des Moines, Iowa, but with much better restaurante.San Salvador has a McDonald's and plenty of taxis. The press hotel, the Vista del Mar, is comfortable though, unfortunately, the capital city is not on the ocean.

Outside the major cities and towns, life is less pleasant because nearly everyone is poor. Poor in El Salvador is different from poor in the United States. These people are really poor.For instance, there are only about 135,000 television sets for a population of 4,260,000. That's 32 people crowded in front of each TV. El Salvador also needs economic aid for development of communications and transportation. This country, if you can imagine, has one telephone for every 60 people, one car for every 100 people. No wonder the buses are so crowded.

The main product is sugar, then coffee, corn and other crops, a little tobacco, a little rice and rubber. We'll get back to the sugar, which has strategic importance. In the hamlets and villages, the main livestock consists of cows, goats, little burros (Burritos ), pigs, many chickens, a few oxen but no water buffalo. In the jungle, there are also great big hairy spiders ("Tarantulas ") which crawl across the roads when it is raining and get run over by the Army jeeps. For logistocal purposes, it will be necessary to pave all the roads running north, east and south from the airport in San Salvador.

The political situation is fairly typical for Latin America. Our government is run by a committee of colonels and generals ("Junta" ) and headed by a civilian named Jose Duarte. His middle name is Napoleon but he is an engineer. Duarte is a graduate of Notre Dame, alma mater of the original Gipper, and speaks good English.

The other side is a motley of overeducated agitators, opportunists and well intentioned but naive rebels who have become Red pawns. They call themselves the Farabundo Marti National Liberation Front (Farabundo Marti is a dead peasant who has the same last name as Jose Marti, the well known Cuban revolutionary wh used to live in New York). Their leader is a Mr. Ungo who used to be pals with our guy Duarte until they had an argument and split. Mr. Ungo is no Ho Chi Minh. He claims to be a home-grown freedom fighter but the famous captured documents make it clear this rebellion is run out of Moscow through the branch office in Havana.

For identification purposes on tactical maps, the FMNLF ("Peligroso ") are known as the Pellies, color-coded red. Our hamlets ("Verdad Sallies ") are referred to as Verdies, color-coded green. At the present time, the map of El Salvador is mostly green but there are a few little red splotches which, if not wiped out soon, could spread their Marxist-Leninist poison across the countryside. This would drive even more peace-loving peasants into the safety of the towns and cities and require early planning on a refugee resettlement program.

In the meantime, the land-distribution program is proceeding far ahead of schedule. According to a cross-cultural comparative scale developed by the Rant Corporation, Salvadoran land redistribution is already 47 percent more effective than a similar program was at the same point in the now-defunct Republic of South Vietnam.

There are problems, however, which no one in authority denies. One problem seems to be that government soldiers have a havit of shooting too many of the peasants they are supposed to protect. They are also shooting the leaders of the new cooperative farms developed under the successful land-redistribution program.

This underscores the need for more training. The Pentagon has developed an excellent course for Sallie officers and the NCOs entitled: "How to Deal with People in an Insurgent Environment." The main lesson in the course will be: Don't shoot the peasants!

One Pentagon official, who didn't want to tell his name, explained it this way to the Associated Press: "The average Salvadoran soldier is a peasant who gets very little training. He's handed a rifle and a uniform and then often put out in small units in the villages to provide security against the guerrillas." On the surface, this might remind some Americans of the ARVN which we trained and modernized in Vietnam (the army that cut and ran in '75), but that is a superficial view.

The Pentagon's idea is to put some heavier weapons into eager hands and send in some more military advisors to train Verdies, only the Americans will not be called "advisors" because that has bad associations.Likewise, the gunboats we send to guard the Golfo will not be called "gunboats" in order to avoir unfortunate headlines.

Many people will ask: What happens if the Marxist-Leninists guerrillas shoot some of the Americans? Won't that lead to pressure for deeper involvement? Pentagon officials have considered the question and dismissed it. iOne official explained that if the enemy guerrillas were to hurt any of our soldiers that would really provoke Uncle Sam "to come down on their necks and they wouldn't want that at all." Shooting Americans nuns is one thing, but shooting American soldiers is called "escalation."

America's leaders, in addition to sending messages through this little war, feel that much more is at stake. El Salvador may be one of the "resource wars of the '80s, which experts have been predicting for several years. Only the resource isn't oil. It's sugar. Try to imagine an American without sugar and you begin to grasp the Commie plan. Forget dominoes. Think sugar cubes. One by one, the Reds take over the sugar countries. They've already got Cuba. With El Salvador, the Red tongs would close on the other cubes.

After sugar, they go after coffee. After coffee, it's bananas. Step by step, the Reds are out to subvert the hearty American breakfast. Without a hearty breakfast, America would fold without a shot. In geopolitics, this is called Finlandizatoin."

Play ball with the Reds or else. We all know what that means. It means Cuba gets a Havana franchise in the National League.