BOISE, Idaho (AP) — Idaho Gov. C. L. “Butch” Otter vetoed legislation Tuesday that would have expressly permitted the use of the Bible in public school instruction, calling the measure unconstitutional.

“I have deep respect and appreciation for the Bible as religious doctrine as well as a piece of historic literature,” Otter wrote in a letter accompanying the veto. “However, allowing S1342 to become law is a direct contravention to the Idaho Constitution and it could result for the loss of funding and costly litigation for Idaho public schools.”

Otter’s decision was his first veto of 2016. He has until Friday to take action on remaining bills.

Idaho public school students are already allowed to reference the Bible and other religious texts in their studies, but the rejected legislation specifically mentions the Bible, stating the book could be used for reference purposes in subjects such as literature, history, music and world geography.

State lawmakers passed the measure in the final week of this year’s session, after ignoring a warning from the attorney general’s office that questioned its legality. A statement released by the office quoted the Idaho Constitution that prohibits the use of books that are of a sectarian or denomination character in public schools.

Conservative lawmakers said the measure would withstand litigation and was needed because the holy book was “under attack.” The measure’s opponents said mentioning the Bible would give JudeoChristian values preference over other religions.

The bill’s sponsor, Sen. Sheryl Nuxoll, R-Cottonwood, said she was disappointed by Otter’s decision and pointed out that the measure passed with overwhelming support in the Legislature.

“People with last names like Washington, Adams, and Madison blatantly identified the Bible as that reference point. They feared not having it would result in corruption and misuse of taxpayer funds. Are they right?” she said in a prepared statement.

The Legislature also wrestled with other religious-themed legislation, including one measure designed to keep Shariah law out of government agencies and court cases. To date, there have been no court rulings in Idaho based on Shariah law. The contentious legislation died after being sent to the House floor for amendments.

Otter’s veto came on the heels of a recent move by Tennessee lawmakers to make the Holy Bible the official state book, despite the attorney general’s argument that the legislation is illegal.

Tennessee Gov. Bill Haslam said he opposes the measure but hasn’t said whether he would veto the legislation.

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