Conservatives want courts to be stingy in creating and expanding constitutional rights -- except when they don't. Liberals want courts to be creative and expansive in interpreting the Constitution -- except when they don't.

This phenomenon was on display in a recent ruling from an appeals court involving the reliably volatile mixture of parents, children, schools and sex. The California-based U.S. Court of Appeals for the 9th Circuit normally serves as Exhibit A in conservative complaints about activist judges conjuring up new constitutional rights. This time around, though, the conservative indictment boiled down to the court's refusal to be expansive enough in applying protections not mentioned in the Constitution. It was, you might say, a case of judicial passivism. A liberal judge gave a narrow, even cramped, reading to the Constitution.

The dispute arose from a survey given to 7- to 10-year-olds in Palmdale, Calif. The school asked parents to sign a consent form and warned that answering questions might make the child "feel uncomfortable." It didn't tell them that the survey included inquiries about sex, including the children's frequency of "thinking about having sex," "thinking about touching other people's private parts" and "touching my private parts too much."

Not surprisingly, when some parents found out their children had been asked such questions, they went ballistic. Equally unsurprising, they went to court, contending that the school's action deprived them of their fundamental constitutional right "to control the upbringing of their children by introducing them to matters of and relating to sex in accordance with their personal and religious values and beliefs."

This case could illustrate the maxim that stupid school districts make bad law -- except that the court managed to get it right despite the school's boneheadedness. A three-judge panel, upholding a lower court, ruled unanimously that the parents, however legitimate their beef with the school, didn't have a constitutional claim.

That the ruling was written by Stephen Reinhardt -- one of the most liberal judges on a liberal court and one of those who ruled against "under God" in the Pledge of Allegiance -- only served to further inflame conservatives. Indeed, the judge seemed to go out of his way to do so: He wrote broadly that parents have no constitutional right "to prevent a public school from providing its students with whatever information it wishes to provide, sexual or otherwise, when and as the school determines that it is appropriate to do so." And he emphasized his allegiance to cases protecting abortion and gay rights -- "They symbolize the importance of our evolving understanding of the nature of the Constitution" -- even as he dismissed the parents' claim in this case.

Conservatives rose to Reinhardt's bait. "Perhaps the most abhorrent example of judicial tyranny in American history," thundered Focus on the Family. Conservative talk radio had a field day -- days, actually. Then the House of Representatives got in on the act, passing a resolution that calls on the full 9th Circuit to rehear the case. The court, said the principal sponsor, Pennsylvania Republican Tim Murphy, "declared parenting unconstitutional."

As over the top as this is, the case presents harder questions than either side acknowledges. The Constitution doesn't mention parents, but the court has recognized constitutional protection for parental rights since the 1920s, when it struck down a state law that barred the teaching of foreign languages, even in private schools, and another that required children to attend public school.

But it would have been stretching those precedents -- and going against the approach of at least three other circuits -- to find a constitutional claim here. It's one thing to say that parents have a right to educate their children as they see fit, another to give them the right to micromanage public schools. As the 1st Circuit said in a similar case, "the schools would be forced to cater a curriculum for each student whose parents had genuine moral disagreements with the school's choice of subject matter."

Yet, if conservatives don't actually have a zero-tolerance policy toward judicial activism, neither can liberals claim particular constitutional consistency. Those who believe, as Reinhardt does (and as I do), that the Constitution should be interpreted expansively enough to embrace protection for abortion and gay rights have a hard time explaining why that approach doesn't encompass a broad view of parental rights.

Yes, parents unhappy with the way the schools are teaching their children have recourse to the democratic process -- just ask the Dover, Pa., ex-school board. But we're not willing -- I'm not, anyway -- to leave, say, abortion rights up to the whim of majorities. The Palmdale parents didn't need the courts to safeguard them; the school said the survey was a mistake and called it off. "I would be upset myself," the superintendent said.

But it's not difficult to imagine a scenario in which constitutional protections seem more fitting. What about a school that required young children to attend sex education classes, even over parental objections? What about a conservative school district that had mandatory abstinence-only sex education classes? Is a parent in that situation really without constitutional recourse?

Defining fundamental rights is a tricky business -- something it would behoove both sides in the legal culture wars to admit more often than they do.