I've been talking to Bill Keyes, head of the group whose efforts have put the tuition-tax proposal on next month's ballot, and I'm fascinated by some of his assumptions.

He assumes, to begin with, that the public schools are going to hell, and that recent reports of improvement are greatly exaggerated. He assumes that the key reason for the decline in public education is the decline in parental involvement, as parents have abdicated to the professional educators. And he assumes that these same parents will get interested again if the schools have not only their children but their money.

It follows from those assumptions that his controversial proposal of a tax credit of up to $1,200 for money parents contribute for their children's private or public schooling will cure what ails education.

The 28-year-old economist (whose only child is a month-old daughter) might find considerable local support for his view that public education isn't what it ought to be, and that a more intense involvement on the part of parents would help to improve it. But to suppose that the tax-credit initiative would lead to parental involvement implies that parents care more for a $1,200 tax saving than for their children.

"You can argue that what's needed is not money but concern," he said. "But that's how you get concern, once people put their money out . . . Our initiative encourages people to get involved in their children's education."

That's one way of looking at it. Another is to say that the initiative would encourage parents who are already concerned to leave the public schools in hope of a miracle that might not be there. After all, nearly all of the better non-public schools already have waiting lists.

"Everybody is laboring under the assumption that there are no spaces left," Keyes said. "But the Catholics say they have buildings--not seats but whole buildings--that are vacant."

It is undoubtedly true that the Catholic schools would be the major beneficiaries of the proposal.

Keyes, who is not Catholic, says he remains a strong supporter of public education. "I come from a long line of public school educators. Both my parents, two grandparents and at least two aunts have all taught in the public schools." He denies that his proposal would destroy the public schools by draining away their resources. "What we would destroy is the ability of the school board and the superintendent to spend money recklessly in the name of public education. When parents have some leverage, you're not going to see (at-large school board member) Frank Shaffer-Corona making phone calls to Iran while the kids come home with ragged textbooks."

Keyes also rejects the notion that his proposal would leave the public schools with only the hardest-to-educate children, who would be rejected by nonpublic schools.

"It's a myth that the public schools are doing anything for these children in the first place," he said. "I recently talked to a woman whose son attended public school and was pushed into a class for the educable retarded, where he was given very little attention. She decided to enroll him in a Catholic school, and now he is a surgeon in Houston, Texas, having completed undergraduate and medical school with honors."

As to the argument that the tax credit would bankrupt the public schools, Keyes says the opposite is more nearly true. "It costs $3,600 to educate a child in the public schools, so every time a parent puts a child in an alternative school, he leaves behind $2,400. If all the public school students left, they'd still have two-thirds of their budget, with no kids to educate."

Still, if Keyes is correct in his assumption that the major problem with the public schools is the lack of parental interest and involvement, doesn't it follow that the chief effect of his proposal would be to siphon off the most concerned public school parents, leaving the public schools disastrously worse off than they already are?

"I used to say the same thing to a friend of mine who was thinking of educating his children at home. I totally reject that view now. He shouldn't make his own kids' education secondary to doing something for the public school system. God holds us responsible for taking care of our own kids first."

Too many parents, he said, have become convinced that they should "just let go and let the teachers take over. When we get to the point where we feel that the institution can do the job for us, we step back--and in every case we find great disappointment."

Which is exactly what we are likely to find if we step back in the expectation that the tuition-tax credit will solve our educational woes. To the extent that parental unconcern is the problem, a $1,200 tax credit seems a long way from the solution.