WASHINGTON — The latest attack on the “godless public schools” — a staple of Republican primaries past — is a new ad in Iowa by Texas Gov. Rick Perry’s campaign proclaiming there’s “something wrong in this country when gays can serve openly in the military, but our kids can’t openly celebrate Christmas or pray in school.”

Advocating for “school prayer” is, of course, a poll-tested winner for politicians seeking to stir voter outrage — and establish Christian conservative bona fides.

Michele Bachmann also took up the cry at a recent town hall in Iowa, declaring that government censors religion in public schools. She added a new twist to the charge by saying that Muslims get to practice their faith in schools, but “Christian kids aren’t allowed to pray.”

The claim that public schools are hostile to Christians may rev up caucus-goers in Iowa, but there’s only one problem: It isn’t true.

Truth be told, students of all faiths are actually free to pray alone or in groups during the school day, as long as they don’t disrupt the school or interfere with the rights of others. Of course, the right to engage in voluntary prayer or religious discussion does not necessarily include the right to preach to a captive audience, like an assembly, or to compel other students to participate.

Visit public schools anywhere in America today and you’re likely to see kids praying around the flagpole, sharing their faith with classmates, reading scriptures in free time, forming religious clubs, and in other ways bringing God with them through the schoolhouse door each day.

As for celebrating Christmas, students are free to say “Merry Christmas,” give Christmas messages to others, and organize Christmas devotionals in student Christian clubs.

It’s true that some public school officials still misunderstand (or ignore) the First Amendment by censoring student religious expression that is protected under current law. But when challenged in court, they invariably lose.

In fact, contrary to culture-war mythology, there is more student religious speech and practice in public schools today than at any time in the past 100 years.

When politicians demonize the courts for banning God from schools, they count on public confusion about the First Amendment distinction between government speech promoting religion, which the establishment clause prohibits, and student speech promoting religion, which the free-exercise and free-speech clauses protect.

The U.S. Supreme Court has never ruled that kids can’t pray in school. What the Court has done — and continues to do — is to strike down school-sponsored prayers and devotional exercises as violations of religious liberty.

As a result of those decisions, school officials may not impose prayers, or organize prayer events, or turn the school auditorium into the local church for religious celebrations.

Students, however, aren’t the government; they can — and often do — openly pray and share their faith in public schools.

When asked to clarify his claim that students can’t pray in schools, Perry said he was objecting to the Supreme Court’s prayer decisions in the 1960s because he thinks local school boards should be free to organize prayers if they so choose. He didn’t say whether he understood that kids are currently free to pray in school on their own.

Apparently, Perry wants to return to the days of school-sponsored prayer, overturning Court decisions by what he calls “activist judges.” If elected, he promises to push for a constitutional amendment to allow it — something Newt Gingrich tried and failed to do when he was in Congress.

If state-sponsored religious practices are what Perry, Bachmann and other candidates mean when they call for “prayer in school,” then why don’t they just say so — and stop telling voters that kids “can’t pray in schools”?

Could it be because they know that most Americans, if given the choice, would prefer the religious freedom students now have over a return to government-mandated prayers?