Last year, between sessions at a conference, I asked a longtime high school teacher in New York City about recent changes to the Advanced Placement U.S. History course framework. Like most A.P. teachers, he praised the revised course's focus on “historical thinking skills.” But he doubted it would make much of a difference. “If colleges don’t teach you how to think like a historian,” he asked, “do you really think high schools can?”

I thought of this exchange on Monday, when an Oklahoma House committee approved a bill to ban state funds from the course. According to the bill’s Republican sponsor, the new framework emphasizes “what is bad about America” and downplays “American exceptionalism.”

That’s been a constant GOP refrain about the revised test, which the Republican National Committee condemned last summer for its “radically revisionist view of American history.” A few weeks later, when a suburban Denver school board resolved to review the test—and to ensure that teachers present “positive aspects of the United States,” as one board member said—thousands of students walked out in protest.

My own guild of academics, the American Historical Association, also rallied in defense of the new A.P. test, which stresses the skills of our discipline—framing questions, sifting evidence, and drawing conclusions—rather than the memorization of facts. But here’s the great elephant in the A.P. classroom: Many college-level instructors don’t teach these skills in their own courses.

In 2005, one-third of undergraduate American history survey courses used a textbook as their only assigned reading; on average, these classes also assigned over two-thirds of their final grade to examinations. Neither practice promises to yield much in the way of historical thinking skills, as a growing body of pedagogical research suggests.