In 1979, weeks after the Sandinistas had seized power in Nicaragua with American help, the Carter administration, though it had been among the first to welcome them, started a covert action program aimed at changing what it called "the emerging totalitarian nature of the Sandinista regime." The Carter administration reasoned, as did the bipartisan Kissinger Commission in 1983- 84, that the United States could not afford to leave Nicaragua in the hands of a regime both totalitarian and allied with the Soviet Union.

Our worst fears are being realized. The Sandinistas are enslaving the Nicaraguan people to the Soviet Union's action coalition, whom they call internacionalistas: the East Germans, who run the secret police system; the Cubans, who run the regular armed forces as well as most ministries; the Vietnamese, who teach guerrilla war, and the PLO, who train people in their grisly specialties.

The Nicaraguan armed forces are larger than those of the rest of Central America combined and are armed with the best equipment the Soviet bloc has. Only the 20,000 fighters of the contra movement, who represent the hopes of most Nicaraguans, stand between the Sandinistas and the "revolution without borders" they have proclaimed. The conquest of Central America is their purpose.

If Central America were to fall, no responsible American should bet that Mexico's ruling class would choose to stand in the way of a Soviet-led anti- Yanqui coalition rather than join it. The Sandinistas with their Soviet "flying tanks" and their internacionalistas will win the war against the poorly armed contras, and we Americans can look forward to a brand new experience: an unfriendly southern border.

Mindful of this, the Reagan administration seems to have ended five years of equivocation about the best way to avoid a communist takeover of Central America. Gone are the illusions that limited support for the contras would safeguard the rest of Central America by interdicting the flow of arms from Nicaragua. The illusions so prevalent in the State Department that some limited support for the contras would lead the Sandinistas to negotiate a long-term agreement with its neighbors, after which we could cut off that support, now stand discredited. Gone are the hopes that the Sandinista leadership might be "bribed" into loosening its grip on its people or its ties with Moscow.

The administration seems to have realized that there is a war in Central America and that the Soviet side is in the process of winning it. Hence the president has proposed that we give to the contras the means not just to fight and die, but also to win. That means helicopters for transport, artillery, antiter missiles. Just as important as the equipment would be the signal that the United States would send to the Nicaraguan people: that the United States is committed to seeing freedom and democracy prevail in their country; if they choose freedom, they and their families will not be on the losing side.

No one in Congress is willing to say outright that the Sandinistas deserve to win over the contras and that the American people would be better off if they did. Few nowadays make what used to be the standard arguments against aid to the contras -- that if we left the Sandinistas alone they would become less dangerous to us. In fact, we did cut off aid last year and saw the Sandinistas become even more brutal to their own people and even more tightly aligned with Moscow.

So the opposition to President Reagan's request relies on blaming the president for his "bad manners" in pointing out that in war, willy-nilly, if one does not support one side, one supports the other. Bt this carping will not erase from an elected official's record the fact that he voted against the side of freedom and on the side of communist tyranny.

When President Reagan said that the American people would hold responsible those who caused a communist conquest of Central America, he was doing nothing more than describing reality. The opposition knows this very well. It knows that by posing the question, "Whose side are you on?" he put them in a thoroughly uncomfortable but thoroughly democratic box.

That is why the opposition is banking completely on the administration to pull it out of this box with some sort of compromise that would keep from the contras what they need to win and would allow the opposition to show that they had voted for something other than a Sandinista victory.

Some "anonymous spokesmen" for the administration are tempted to make such a compromise out of fear of losing, and because their vote-counters in Congress are ignorant of one basic fact: on "tough" issues, ones on which they would rather not vote, members often vote differently from the way they declare beforehand. "I'll vote against you" often means, "Please don't make me vote." Unless the administration is actually willing to risk a defeat and then make those who defeated it bear public responsibility for what follows, it will always lose the tough ones by agreeing to compromises that in the end don't even save face.

In fact, there is a strong case to be made for giving the contras enough to win. There is a much weaker case for doing all we can to come to terms with Soviet power on our continent. But there is no case at all to be made for continuing to help keep men in the field to die, while further antagonizing a Sandinista regime headed for supremacy in Central America.

Unfortunately, this worthless alternative is the one most appealing to many politicans at both ends of Pennsylvania Avenue. A compromise that fudges a commitment to the victory of freedom is the worst of all possible worlds.