NICARAGUA has put on its Halloween costume and is going trick-or-treating at every American door.

You hear the door bell ring, and you answer it. And you say, puzzled, "And what are you, my little cute thing?"

"I'm the ghost of Vietnam," comes the reply.

A wraith is walking down every American street, knocking on every American door, six months after Halloween, 13 years after Vietnam. Nicaraguan president Daniel Ortega is putting a spook into every American home. Ronald Reagan is letting him in.

By sending more than 3000 troops to Honduras this week, ostensibly in defense of democracy, Ronald Reagan is letting an anachronism stalk the earth. A trick-or-treater in March. The ghost of a war we thought we had buried in 1975.

"We are ready to fight these forces of the 82nd Division because the Superman was defeated in Vietnam and will again go out of Nicaragua defeated if it lands here with its bombers, helicopters or whatever it brings," Ortega said two days ago.

DING-DONG. How cute. You must be Casper, the friendly ghost. "No, no. I'm the ghost of Vietnam."

Ronald Reagan's recent foray into military machoism comes on the heels of a discovery that half of American high school students can't place the United States properly on a world map. How many of these kids, one wonders, know where Honduras is? And how many of these kids would be sent there, and even be buried there, should that ghost come alive?

Ronald Reagan is more concerned with communism down the block than ignorance in his own home. Instead of sending young men and women off to fight the next Vietnam, he should make sure they know what the first one was. In the long run, education--because it teaches cooperation--is a more potent weapon than a gun or missile.

A man who does not have his own house in order should not try to redecorate his friend's.

Reagan has added his two cents to the philosophical debate over mind and body. Why use minds to figure out workable solutions to international problems when you can send a bunch of bodies to do the talking--and the philosophizing--for you? Forget the Arias Peace Plan. Let's win one for the Gipper.

REAGAN has always been a "Can Do" president. A touch of turmoil in Granada? Send troops. Problems with hostages in Lebanon? Send arms to Iran.

The problem with Reagan's foreign policy is that there is no underlying strategy. What Reagan doesn't like, he attacks--or, barring that, tries to get rid of it in the most expeditious way. He is like the typical Western gunslinger. Shoot first, and ask questions later.

When the history of United States international affairs under Ronald Reagan is written, it will be a series of unconnected sentences, a stream-of-consciousness ditty.

Sure, Ronald Reagan can do. But can he think?

One thing the Army's "Be All You Can Be" advertisements never mention: the real job is to kill. Being in the Army is a holiday--"See Europe and the Far East for free"--until you have to punch the clock and go to work. Today, soldiers' faces stare out at us from front pages and television screens. The whistle is blowing. The coffee break is over.

We didn't have to wait for Ted Kennedy or Alan Cranston or any other liberal lawmaker to damn Reagan's actions by mentioning our only ill-fated war. Nicaragua was the first to bring up Vietnam.

The fact that the word "Vietnam" still stings should warn us to be cautious as we again try to help out a neighbor.