We used to have a problem with illegal aliens, but it no longer exists.

Two years ago, Leonard F. Chapman Jr. then head of the Immigration and Naturalization Service, told Congress that between 8 and 12 million illegal aliens were already in this country. A million more were arriving each year.

Congress was concerned because illegal aliens compete for jobs with the very people who swell the ranks of the unemployed among our own citizens: minorities, the young, the unskilled, the handicapped. So Congress told Chapman to get cracking on the task of finding and deporting illegal aliens. Yessir, we had quite a problem in those days.

But everything is just peachy now that Leonel J. Castillo is INS commissioner. The Environmental Fund says Castillo "has issued instructions that INS personnel stop giving out any information regarding estimates of illegal aliens residing in this country. He himself suggested that there were only 2 or 3 million of them."

Obviously one of those two commissioners is full of baloney. They can't both be right.

The Environmental Fund also states that Castillo has ordered INS personnel to fool the Congress with a "label swindle" by ordering that the term "illegal alien" be replaced by the term "undocumented worker." Congress told INS to root out illegal aliens, not undocumented workers.

So the latest is that INS will no longer conduct raids in areas where "undocumented workers" are known to live, work and congregate. The problem has vanished.

I am reminded of a stormy Cabinet meeting presided over by Abraham Lincoln. At one point the arguments became so heated that Lincoln decided it was time to get his advisers back on a logical course again. "Gentlemen," he said, "let us see if we can agree on a few facts. How many legs has a cow?"

They all said a cow has four legs. "Good," the president said. "We have agreed on something. Now if we call the cow's tail a leg, how many legs would she have?"

"Five," the cabinet said in unison, and Abe looked pained.

"No, no," he said sadly. "That's where we've been getting off the track. Calling the cow's tail a leg doesn't make it a leg. She'd still have four."

If Mr. Lincoln were contemplating the magical disappearance of our illegal alien problem, he might comment that squirting perfume on illegal aliens and calling them "undocumented workers" doesn't change anything, either. They're still illegal aliens, and they're still a problem that Commissioner Castillo will be content to leave unsolved. He favors a policy of amnesty for illegal aliens.