A federal court is blocking implementation of a regulation that would make an estimated 4 million more higher-earning workers eligible for overtime pay.

The U.S. District Court in the Eastern District of Texas granted a nationwide preliminary injunction Tuesday that prevents the Department of Labor from implementing the changes until the rule's legality can be further examined. The order comes after 21 states sued to block the rule before it took effect on Dec. 1.

The lead plaintiff was Nevada Attorney General Adam Laxalt, who's a frequent critic of what he calls Obama Administration overreach.

The regulation would shrink the so-called "white collar exemption" and more than double the salary threshold under which employers must pay overtime to their workers.

Laxalt said the rule would burden private and public sectors.