In his second debate with Walter Mondale last fall, and again in a news conference in February, President Reagan made out as if he'd originally been a supporter of the Sandinista revolution in Nicaragua -- until the Sandinistas let him down. "And once victory was attained," he said, sadder but wiser, "the Sandinistas did what Castro had done prior to their time in Cuba" -- namely, abandoned the idea "that their revolutionary goal was for democracy, free press, free speech, free labor unions and elections and so forth."

First of all, Reagan didn't really support the Sandinistas. Jimmy Carter may have believed they wanted democracy, but Reagan didn't for a minute. "While there are people in that troubled land who probably have justified grievances against the Somoza regime," he said in 1979, just before the Nicaraguan revolution, in a radio broadcast quoted in Ronnie Dugger's book "On Reagan," "there is no question but that most of the rebels are Cuban-trained, Cuban-armed and dedicated to creating another Communist country in this hemisphere."

Why would Reagan go to the trouble of creating this stretcher about his hopes for the revolutions in Nicaragua and Cuba? In this as in other areas where he's self-contradictory, he is faithfully reflecting the contradictory views of the American people. We may not like Soviet allies in our back yard, but we still find the word "revolution" and the idea of a people's rising up to throw off the shackles of oppression deeply appealing. How could we not? Our own country stands as history's best advertisement for revolution.

But it seems that they aren't making revolutions like they used to; anyway, the truth underneath Reagan's professions of dashed hope is that we're against most of them these days.

One reason is that, once you get a quarter-inch underneath the rhetoric of liberation, the Marxist/Leninist model of revolution bears almost no similiarity to the American model. Read, for example, Lenin's "What Is to Be Done" or John Reed's "Ten Days That Shook the World," and it's instantly clear that democracy was never in the script. The Russian Revolution consisted of the most extreme, ruthless and disciplined of many warring factions taking control and immediately abolishing freedom of expression and putting all power in the hands of the party. Mikhail Gorbachev isn't going to change this. For more than 60 years, the claim made for communist countries by sympathetic visitors has been that they have eliminated crushing poverty for a huge peasant class -- never that they're lands of liberty.

Besides that, the strength and spread throughout the world of the two superpowers makes it very unlikely that a revolution that takes any time can still be truly indigenous by the time it succeeds. We're not playing Lafayette in Nicaragua, and neither are the Soviets in El Salvador; if either of those revolutions succeeds, the resulting government will be a hundred times more a client state than we were after Yorktown.

So what should we really feel -- not pretend to feel or want to feel -- about revolutions?

Our true policy now, founded in a tough, us-and-them view of the world, is to support essentially all revolutions against communist governments, and all non- communist governments against revolutions. A more forthright Reagan would have said he was against the revolutions in Cuba and Nicaragua because those countries used to be our allies and aren't any longer.

It's tempting, though, to look for another way, one that would let us support revolutions against the world's worst governments: Afghanistan and Poland, but also South Africa and Chile and the Philippines.

We'd be doing this in hopes of gaining a strong, loyal ally, and also because maybe somewhere revolutions still can replace tyranny with liberty and make life both freer and better.

But we'd be careful. We wouldn't undermine one undemocratic regime so that a much worse one might take its place, as in Iran. We wouldn't trust "democratic Marxists," who seem always to disappoint us in terms both of democracy and of our interests. We would pamper the new regime lavishly at first, so that it doesn't fall into the Soviet embrace.

Ah, you might think, dream on.

But isn't that better than having to go around perpetually broken-hearted, or pretending to be?