(NRN) - Twenty-one states have joined forces to challenge the U.S. Department of Labor’s new overtime rules in a lawsuit filed in a Texas federal court Tuesday.

The attorneys general of Texas and Nevada filed the lawsuit in U.S. District Court for the Eastern District of Texas, calling the overtime regulations “illegal” because they are set to ratchet up the threshold for eligibility automatically every three years without valid congressional authorization, according to a statement from Texas attorney general Ken Paxton.

The complaint also contends that the new rules, which are scheduled to go into effect Dec. 1, will substantially increase labor costs for many states, local governments and private businesses, and will likely result in layoffs and job elimination.

“Once again, President Obama is trying to unilaterally rewrite the law,” Paxton said in a statement. “And this time, it may lead to disastrous consequences for our economy. The numerous crippling federal regulations that the Obama administration has imposed on businesses in this country have been bad enough. But to pass a rule like this, all in service of a radical leftist political agenda, is inexcusable.”

Joining Texas and Nevada in the lawsuit are Alabama, Arizona, Arkansas, Georgia, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Michigan, Mississippi, Nebraska, New Mexico, Ohio, Oklahoma, South Carolina, Utah and Wisconsin.

The new rules would raise the threshold of eligibility for overtime from $455 per week to $913 per week, or $47,476 annually. Under the shift, an estimated 4.2 million more workers across the U.S. would be eligible for overtime pay.