Do religious issues sway voters?

Just how important to voters are candidates' views on religious issues? The implication, as candidates take strong stands for or against legalized abortion, prayer in the schools, and tuition tax credits, is that many votes hinge directly on those positions.

But a number of academic experts who closely watch the religion-politics connection, say this appearance is deceptive, particularly in national races. Voter behavior is not influenced that much by such issues, they say.

''Religion is a marvelous, exciting, heater-up of temperatures,'' says Martin Marty, who teaches modern religious history at the University of Chicago. ''But for the most part in the political world, it's not decisive. It doesn't convert. It confirms.''

As Professor Marty sees it, voters tend to base their choices on a broad mix of factors. Candidates' views on religious issues, then, serve largely to confirm a choice already made for other reasons.

''I don't see 1984 as a social-issue election - there's never been any evidence that such issues are really very important to a large proportion of the electorate,'' says political scientist R. Booth Fowler at the University of Wisconsin. ''The secret, of course, is to have politicians believe that voters are influenced, and some religious groups have been rather successful in creating that impression.''

''There are some one-issue voters, but it's nothing close to a large proportion of the electorate,'' agrees William McLaughlan, a Purdue University political scientist. Still, in a close presidential election, he says it's possible that a small voter pool, influenced by highly visible advocates of single-issue politics such as the Moral Majority's Jerry Falwell, could make a difference in some states.

One advantage that groups like the Moral Majority have over Roman Catholic bishops in trying to influence voter choices, says Chicago Professor Marty, is that the latter's listeners have tended to be more politically passive. Thus, recent efforts by conservative Protestant leaders to increase voter registration can make a difference.

Indeed, Washington University political scientist Robert Salisbury notes that in 1976 President Carter received a ''considerable boost'' from conservative evangelical Christians, who voted in greater numbers than usual and opted for a Democrat when they might ordinarily have chosen a Republican.

But Professor Salisbury says efforts to politically mobilize congregations ''from the pulpit'' have been neither extensive nor effective. In his view, one reason for this is that the national leadership of groups such as the National Council of Churches and the clergy generally (with the exception of some fundamentalists) tend to take more liberal positions than those of their memberships.

Even the church hierarchies within a denomination do not necessarily speak with one voice, notes Wisconsin's Dr. Fowler. Another reason for religious leaders' lack of influence on voter behavior, he says, is that they have not proved adept at building coalitions with one another. He notes that, while Catholic leaders agree with conservative Protestant leaders on the abortion issue, for instance, the Catholic bishops' pastoral letter condemning nuclear war is more in line with liberal Protestant views.

But does all this talk by religious groups and candidates tend to blur the line drawn by the Constitution that separates church and state?

''Apart from a few little technicalities, people are playing the rules of the game,'' says Professor Marty. ''I'm for religion in public life wherever it's part of the package deal of who a candidate is ... but I do see some things that aren't illegal but I think are bad policy and that make me nervous as a Christian.''

''There's a kind of continuing tension, but I don't see any significant or dangerous intermingling,'' says Washington University's Salisbury. ''Most of the controversies lately have been about very small questions.'' Indeed, he argues, there has been progress in recent years to tighten the relaxed interpretation of the separation principle that had been allowed to occur in ''fact.''

''It used to be that, despite the First Amendment, there were all kinds of observations and ceremonies permitted and encouraged in public places.'' He says he is referring particularly to Christmas ceremonies and displays in both public schools and local government. ''Now there is much more insistence on separation as a matter of fact,'' he says.

But Wisconsin's Fowler says polls indicate that the majority of Americans consider themselves to be religious and favor prayer in schools. ''There's obviously considerable belief that religion should play a role in public life as long as it's not a single religion - that's what separation of church and state increasingly seems to mean.'' To Fowler, the new law that allows student-initiated religious meetings to take place in public schools during off hours is one of several recent signs that there is a role for religion but that pluralism will prevail.

''The (meetings) law is not nearly as much of a violation as prayer in the schools, which would clearly privilege religion over nonreligion,'' says Chicago's Marty. ''On the scale of egregiously offensive violations, I don't think there's a fundamental problem in having a building, paid for by taxpayers, used by all kinds of people.''

But Purdue Professor McLaughlin is less sure.

''I think it's potentially dangerous because it gives a substantial advantage to those groups who see proselytizing as an appropriate way of getting members, '' he says. ''The more cracks or chinks in the wall (of separation between church and state), the greater the potential for infiltration. I'd rather see the wall maintained.''