Fight bad speech with more speech. I don't approve of what you say, but I'll defend to the death your right to say it. That's what my fellow liberals say -- unless the speech in question is religious. Witness the recent dust-up in Kountze, where school district officials had barred cheerleaders from displaying Bible verses on banners at their football games. A judge granted a temporary injunction to the cheerleaders, letting them display the banners until a court hearing in June.The injunction triggered celebrations in Kountze but outrage from liberal organizations, which invoked America's venerable tradition of church-state separation. The banners are part of a school-sponsored activity, liberals argued, so they violate the First Amendment's ban on government endorsement of religion.But I think they've got this one wrong. The First Amendment also guarantees the free expression of religion, as well as freedom of speech writ large. Sure, the banners were displayed at a school event. But they were generated by the students, not by the school itself. And that's how they're different from the pregame prayer in Santa Fe, another small Texas town that became the focus of church/state controversy in the 1990s.By long-standing tradition, Santa Fe High School's elected student chaplain delivered a prayer over the public address system before each football game. After Mormon and Roman Catholic families filed a motion to block these exercises, which they described as Protestant proselytizing, the school proposed a student referendum to determine whether the prayers should continue. And if the pro-prayer side won, the school declared, it would hold a follow-up election to choose the student who would lead the pregame worship.But both practices violated the First Amendment's establishment clause, as the Supreme Court correctly ruled in 2000. Not so for the cheerleaders in Kountze, who reportedly designed the banners on their own and even bought their own supplies to make them. It's hard to see how their speech reflects the imprimatur of the school, or violates the establishment clause.But it does raise a question: Would the cheerleaders' defenders rally in support of students putting up banners with passages from the Quran or Confucius? At a press conference held in support of the cheerleaders, Texas Gov. Rick Perry answered yes.So, in line with the principle of challenging speech with speech, I urge every liberal organization to converge on Kountze with banners quoting other religious texts. We'll find out soon enough whether Perry and Co. really believe in free expression. Would this exercise trivialize the other faiths? Possibly. But there are plenty of Christians who think that game-day football prayers mock their faith. Their ranks included the famously devout Dallas Cowboys coach Tom Landry, who said that on-field prayers "mislead people and belittle God."I find the whole concept of game-day prayers absurd. Why do players and fans thank God when they win, but never blame him when they lose? And doesn't he have more important things to worry about than a football game?But, as a card-carrying liberal, I stand by the right of people to disagree with me. And I'm especially delighted that the conservative side now wants to protect students' free speech, after years of trying to muzzle it."No student should ever have to leave his or her religious expression at the schoolhouse gate," one of the cheerleaders' attorneys said last week. The gate metaphor comes straight from Tinker v. Des Moines, the Supreme Court's landmark 1969 ruling allowing students to wear antiwar armbands in school.Since then, liberals have struggled to protect student free-speech rights and conservatives have chipped away at them. In 2007, for example, the conservative majority on the Supreme Court barred an Alaska high school student from displaying a banner declaring "Bong Hits for Jesus."The Kountze cheerleaders delivered a more reverent message about Jesus, of course. Just like the Alaska student, though, they invoked the Tinker case. Liberals should be happy about that. And they should rededicate themselves to protecting all student speech, no matter how pious -- or impious -- it might sound.Jonathan Zimmerman teaches history and education at New York University. He is the author of Small Wonder: The Little Red Schoolhouse in History and Memory.