The Vatican's Sacred Congregation for Catholic Education recently issued a statement calling for government money for parochial schools. The request will go unheeded in the United States because there aren't enough pro-Catholic-school voters to convince the Supreme Court a subsidy would not be unconstitutional.

The Constitution prohibits any law tending toward the establishment of religion, but no possibility exists of that coming to pass. America's 18th Century political thinkers had a precise definition of what constituted an established church, a definition which came from the miserable religious feudings of the previous two centuries. The closest we'll get to reliving the confessional atrocities of Bloody Mary or Charles I is the insertion of the phrase "under God" in the Pledge of Allegiance.

In actuality, of course, Catholic schools do receive some state aid. They are tax-exempt and certain minor amounts of public money are licitly spent on Catholic schoolchildren. Why it should be constitutional to make such schools tax-exempt but unconstitutional to pay for the oil to heat them has never been satisfactorily explained. The realistic conclusion is that the constitutional argument is a convenient one for judges and other pols to hide behind when being implored by churchmen for money and threatened by anti-churchmen if they dare give it.

The Vatican says that church schools ought to be helped "in the face of materialism, pragmatism and the technocracy of contemporary society." According to Rome, parochial education is alive with "those who are building a new world - one which is freed from a hedonistic mentality and from the efficiency syndrome of modern consumer society."

There are church schools in this country that do strive in their own peculiar ways, to do what the Vatican wishes Catholic schools would do. The most notable are the Amish, the ancient Anabaptist sect which doesn't believe in buttons on their clothes or motor cars. For decades they've been resisting the pressure to have their children schooled like everybody else and have gotten precious little help from the Catholic hierarchy or religious muckety-mucks of other flavors.

Hence the first objection to giving money isn't constitutional, but skepticism as to what we're likely to get in return. What we can hope to get back is a small measure of diversity.

One of the objections which can be made to public education is that it is mainly designed to convert human beings into lock-stepped robots for the labor force. From Horace Mann forward, its use and necessity has been explained and advocated as a means of homogenizing and training personnel to be components of a social system. The effort hasn't been entirely successful. A certain number of recalcitrant young blacks and other similarly situated youths persist in throwing spitballs, but most kids conform to the shape of the school system's cookie cutter.

The obverse side of the problem is whether the government can bring itself to give money to church-related schools without demanding the recipients adhere to HEW guidelines. The whole point in granting the subsidies is the hope the schools will be different, although not necessarily better, academically. There are more expeditious ways of pulling up the kids' reading achievement scores than passing out dough to church schools.

In the past, American oultural institutions have been hostile to most forms of diversity. Under the gun of the '60s, money was allotted to bilingual programs for Hispanics and African-study projects for blacks. The tradition though, has been to fear that from diversity comes disunion, and it is that, more than the First Amendment, that will keep the church schools from getting money.