JEFFERSON CITY- Three Missouri taxpayers are suing to stop the state from providing money to a multi-state consortium that’s developing tests tied to the new Common Core education standards.

The Jefferson City News-Tribune reports that the lawsuit was filed last week in Cole County Circuit Court. The suit calls the Smarter Balanced Assessment Consortium an “illegal interstate compact not authorized by the U.S. Congress.”

Plaintiffs include suburban St. Louis businessman Fred Sauer. He was an unsuccessful Republican candidate in the 2012 gubernatorial primary.

The Common Core standards are unpopular among some conservatives. The uniform set of benchmarks for reading, writing and math replace a hodgepodge of educational goals that had varied from state to state. Backers say they are more rigorous, while critics fear they will set a national curriculum.