No one should have been surprised by the Supreme Court’s 5-4 ruling that school vouchers are constitutional. You could see it coming.

The controlling logic was laid out two years ago by Clarence Thomas, when the court permitted the spending of taxpayers’ money to provide computers for all schools public, private and parochial.

On that occasion, and again Thursday in the case of the Cleveland voucher plan, the winning argument was that programs are constitutionally acceptable meaning they don’t run afoul of the First Amendment ban on governmental action “respecting an establishment of religion” so long as they treat religious and nonreligious institutions the same.

Writing for the majority in the voucher case, Chief Justice William Rehnquist found that the Cleveland program is “entirely neutral with respect to religion,” provides “genuine choice” and therefore “does not offend the Establishment Clause.”

But on vouchers, constitutionality is only the threshold question. The larger issue, still to be engaged nationally, is whether vouchers make for good public policy.

My view is that they don’t, at least as practiced thus far. For me, vouchers make more sense in theory than in reality.

There is, I must say, something extraordinarily attractive about the concept, this idea of government’s giving a poor child trapped in a failing school district a ticket out. At first glance, that option sounds far better than making the child lose years waiting, perhaps in vain, for changes in funding formulas, reductions in class size and the arrival of new textbooks.

Thomas captured that sentiment in his concurring opinion Thursday, proclaiming: “While the romanticized ideal of universal public education resonates with the cognoscenti who oppose vouchers, poor urban families just want the best education for their children, who will certainly need it …”

As I read that, it struck me that vouchers have been far more “romanticized” than public education, whose warts we know. Voucher systems have problems all their own.

Let’s start with the size of the chit. In Cleveland, it’s $2,250, more in Milwaukee and in Florida, the only other jurisdictions that currently have such programs. But in no case is it enough to provide students and parents with a wide range of choices, in those few locales where a big number of alternative schools actually exist.

About the only place where $2,250 gets you in the door is the parochial school system. In Cleveland, 82 percent of the schools that accept vouchers are religion-based, and those schools have attracted 97 percent of voucher students. The numbers reflect financial reality more than free will; nearly two-thirds of those attending a religious school on vouchers do not embrace the religion.

There is one benefit to such modest vouchers: They do relatively little financial damage to the public school system. If and when vouchers become big enough to provide genuine choice, though, they will do real harm to public education and the millions of children who’ll remain there.

Again, it’s a matter of theory versus practice. In theory, when you take one child out of a public school and take away the dollars spent educating him the system is whole. In practice, it doesn’t work that way. Remove one child from a school, and you’ve saved almost nothing; you still need the teacher, the classroom, the heating, etc.

Yes, as voucher advocates claim, the competitive pressure caused by giving parents more choices might push the public schools to get better, but not in ways that require money. In fact, vouchers would likely provide officials with an excuse to shortchange low-performing schools.

Finally, there’s the question of accountability. If we as a society use dollars from the public treasury to start sending students to private and parochial schools, don’t we then have the right to make some of the same demands on them that we now make on public schools? Won’t that raise a whole new set of church-state issues?

I’m not opposed to pilot programs. I’m not closed to the idea that there might be a way for vouchers to help the some without hurting the many. But I haven’t heard it yet.

At this point, I can’t see how vouchers are the primary answer to what ails American education. Even now that they’re constitutional.

Larry Eichel is a columnist and editorial-board member for the Philadelphia Inquirer. His e-mail address is leichel@phillynews.com.