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

In the veto's accompanying letter Otter said he respected the Bible, but the measure would result in costly litigation for Idaho's public schools. He said the measure directly contradicts Idaho's Constitution. The bill stated the Bible could be used for reference purposes in subjects like literature, history, music and world geography in public schools, but not scientific subjects.

Schools are already allowed to reference the Bible and other religious texts, but this legislation specifically mentioned the Bible. The Legislature 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.