An Arizona charter high school allegedly required its students to read a conservative author beloved by pundit Glenn Beck and considered one of the philosophical forebears of the tea party, according to a complaint filed last month by a national watchdog group.

The complaint against Heritage Academy, following up on a December letter, was filed by Americans United for the Separation of Church and State. Heritage Academy is located in Mesa, Ariz., and expects to enroll 650 student next year, according to the Arizona Republic.

AUSCS alleged that Heritage required its senior students to read W. Cleon Skousen’s “The 5,000 Year Leap,” according to the complaint, and the school admitted that it was used as part of its curriculum. The group has also alleged that the school includes Skousen’s “The Making of America” as required reading for its senior government classes.

Skousen’s books “actively promote and endorse specific religious views and ideologies,” according to the complaint, noting that the author asserts that the Founding Fathers were inspired by ancient Israel and pointing to certain chapter titles like “All Laws Should Be Measured Against God’s Law” and All Men Can Be Taught God’s Love and Virtue.”

The complaint alleges that Skousen’s books also suggests that the world would be “happier” if United States never intervened to stop the Holocaust during World War II and cite other essays that “appear to paint slavery in a positive light.”

As Mother Jones reported in 2010, Skousen has served as a particularly ripe source of inspiration for Glenn Beck and, by extension, many in the tea party movement. Beck has said that Skousen’s Mormon-based philosophy provided much of the basis for his own 9/12 Project and authored the forward for a new edition of “The 5,000-Year Leap,” according to the liberal magazine.

And, as a local tea party leader told the Republic, Skousen, who died in 2006, is “well known among tea party members.” The Southern Poverty Law Center described him as “a minor legend in the annals of right-wing radicalism” prior to Beck’s endorsement, which led to significant posthumous popularity.

According to the AUSCS complaint, Heritage Academy officials contended that Skousen’s books were not religious but “only teach about the religious influences in the nation’s founding.” Along with its letter last month, the group provided state officials with hard copies of the books for their own review.

The school’s founder and principal Earl Taylor gave a similar comment to the Republic: “Our purpose is not to convert students to different religious views,” he said. Other authors in its syllabus include Benjamin Franklin, Anne Frank and Karl Marx.

The group demanded that the school stop including the books in its curriculum or have its charter be revoked by the state. Alex Luchenitser, the associate legal director for AUSCS, told TPM in an email that they would consider litigation if necessary.