Governor Bill Haslam allowed Tennessee's House Bill 368 to become law without his signature on April 10, 2012, according to the Memphis Commercial Appeal (April 10, 2012). The law encourages teachers to present the "scientific strengths and scientific weaknesses" of topics that arouse "debate and disputation" such as "biological evolution, the chemical origins of life, global warming, and human cloning."

In a statement, Haslam explained, "I have reviewed the final language of HB 368/SB 893 and assessed the legislation's impact. I have also evaluated the concerns that have been raised by the bill. I do not believe that this legislation changes the scientific standards that are taught in our schools or the curriculum that is used by our teachers. However, I also don't believe that it accomplishes anything that isn't already acceptable in our schools. The bill received strong bipartisan support, passing the House and Senate by a three-to-one margin, but good legislation should bring clarity and not confusion. My concern is that this bill has not met this objective. For that reason, I will not sign the bill but will allow it to become law without my signature."

"This is the first bill in Haslam's nearly 15 months in office that he has allowed to become law without his signature," the Commercial Appeal noted, adding, "Although the governor didn't say so, a veto would likely not have killed the bill" because the legislature can override a gubernatorial veto by a majority vote in both chambers.

NCSE's executive director Eugenie C. Scott expressed disappointment, warning, "Telling students that evolution and climate change are scientifically controversial is miseducating them. Good science teachers know that. But the Tennessee legislature has now made it significantly harder to ensure that science is taught responsibly in the state's public schools." Citing a recent article in Inside Vandy (April 8, 2012) reporting disagreement among the bill's sponsors about whether "intelligent design" creationism was covered, she argued, "if the people who are responsible for passing the law can't agree on what it covers, they shouldn't be saddling teachers and school districts with the task of figuring out what it means."

Probably contributing to Haslam's unwillingness to sign the bill were the protests from state and national civil liberties, educational, and scientific groups, the editorials against the bill from the state's major newspapers, and the petition effort organized by Larisa DeSantis of Vanderbilt University, which garnered thousands of signatures calling for a veto of HB 368.