AUGUSTA, Maine (AP) — Maine laws protect people from discrimination based on factors such as race, disabilities and sexual orientation, and a Republican lawmaker wants to add a person’s beliefs about climate change to that list.

Rep. Larry Lockman has introduced a bill that would limit the attorney general’s ability to investigate or prosecute people based on their political speech, including their views on climate change. It would also prohibit the state from discriminating in buying goods or services or awarding grants or contracts based on a person’s “climate change policy preferences.”

Lockman, an independent business consultant from Amherst, told The Associated Press that he believes it’s an open question whether human activity is the primary cause of climate change.

“We need to have a vigorous public debate on that question,” he said.

Peer-reviewed studies, science organizations and climate scientists say that the world is warming from man-made forces.

Rep. Lois Galgay Reckitt, a Democrat of South Portland and a marine biologist who sits on the judiciary committee that has the bill, said prospects for passage are poor. She said she expected “the entire Democratic caucus is going to hate it,” and some Republicans will, too.

“The issue for me is I’m a scientist and I live near the ocean. It’s absolutely clear to me that climate change is happening, and it worries me,” she said. “I will fight this tooth and nail.”

Lockman wants to prohibit the state attorney general from investigating, joining an investigation or prosecuting any person based on that person’s protected political speech.

But he said his bill would also reaffirm free speech by protecting climate change supporters as well.

“I don’t want to see a Republican state attorney general issuing subpoenas for the records of progressive or liberal think tanks or public policy groups to chill their free speech,” he said.

Democratic Attorney General Janet Mills declined to comment.

In his bill, Lockman says that the Supreme Court’s decision in Citizens United “continued the protection of protected political speech, no matter the source or message.” That case allowed corporations and unions to make unlimited independent expenditures in U.S. elections.

Jonathan Reisman, an associate professor of economics and public policy at the University of Maine at Machias and a vocal critic of the scientific consensus on climate change, said he requested the bill.

He said the bill is an attempt to defend the First Amendment freedom of those who speak out in a way that does not reflect the consensus.

“It’s about Citizens United and the government abridging speech,” he said. “It’s not about climate science. It’s about climate policy.”

Lockman has a history of causing controversy. He once dressed as a vampire outside a federal building in Bangor to protest the Internal Revenue Service. He also once accused liberals of assisting the AIDS epidemic, saying they assured “the public that the practice of sodomy is a legitimate alternative lifestyle, rather than a perverted and depraved crime against humanity.”

He said he couldn’t predict the outcome of his latest bill but expected a lot of interest at a public hearing scheduled April 6.

Lockman’s bill is “absurd and unnecessary,” said Dylan Voorhees, climate and clean energy project director for the Natural Resources Council of Maine.

“Clearly an attempt to provide cover for climate deniers,” he said. “I see a trickle down from the Trump administration that has emboldened some folks to make climate denial statements.”