If you are a school superintendent setting up a magnet school, you can probably get federal aid to support it. Congress passed a law last summer, and it's now taking effect. But under that law you are going to have to make a firm commitment. You are going to have to promise not to use any of that money to teach "secular humanism."

Well, you say, okay, but just what does the federal government mean by "secular humanism"? That's the fun part. Congress didn't tell you, and it instructed the Department of Education not to tell you. It's up to you and your school board to define it. Or perhaps it's up to a federal judge, if you should be sued by one of the many religious organizations and parents' groups that currently use "secular humanism" as a general designatin of all that they most dislike in the public school curriculum, from the theory of evolution to the literature of protest.

How did such an eccentric and offensive prohibition get written into law? The usual way. There are many friends of the public school in Congress, and they yearn to vote more money for education. But there are not quite enough of them to ensure passage, and they pick up support on the right by letting in language like the secular humanism clause. In this case it was Sen. Orrin Hatch who imposed it as a kind of a toll on the bill as it went through the Labor and Human Resources Committee, of which he is chairman.

It's a bad habit, this practice of buying votes for money bills by inserting language that can only inflame local controversies. Congress likes to take the credit for providing the money, but it is gratuitously making trouble for school boards all over the country. The secular humanism rule applies only to the money for the magnet schools. But it sets a precedent, and provides further grounds for legal attack on the schools and what they teach. It's not an isolated example. It's in the same bill in which Congress also told local schools that they must give religious groups access to school rooms on the same terms as other extracurricular activities.

When federal aid to schools first began its great rise with the passage of the Elementary and Secondary Education Act just 20 years ago this spring, many conservatives feared that the money would become an irresistible vehicle for imposing political conditions and standards on local schools. That does indeed seem to be happening -- in a small way, so far, but not insignificantly. Conservatives were right to be concerned about the possibility in 1965, and they would be right to be equally careful about it 20 years later.