NEW YORK -- The failure of US public education to provide a complete account of the country's history limits democracy, two scholars warned in an op-ed posted last week in The New York Times.

"Public education requires lessons about history," but many states have proposed laws to limit teaching about the full picture of US history, said Heather McGhee, author of "The Sum of Us: What Racism Costs Everyone and How We Can Prosper Together," and Victor Ray, author of "On Critical Race Theory: Why It Matters & Why You Should Care."

According to the nonprofit organization PEN America, legislatures in 36 US states have proposed 137 bills limiting teaching about race, gender and American history. Nineteen censorship bills have become law in the past two years.

"When partisan politicians ban the teaching of our country's full history, children are purposely made ignorant of how American society works," the two authors warned.

They advocated for an education that shouldn't "shy away from America's ugly truths and contradictions."

Referring to contemporary attacks on teaching true history, McGhee and Ray said they are authoritarian attempts to impose a sanitized curriculum, urging that "schools shouldn't cheat kids by denying them the tools to navigate the world as it exists - and to create a better one for all of us."

"If an educated citizenry makes democracy possible, attacking schools becomes a proxy war to limit democracy," the scholars said, calling for US parents and grandparents to fight back.