A group of 11 states and Washington, D.C., are suing the Trump administration in an attempt to roll back a regulation that allowed for the expansion of certain health plans that skirt ObamaCare regulations.

The lawsuit, led by New York Attorney General Barbara Underwood (D) and Massachusetts Attorney General Maura Healey (D), alleges that the Department of Labor violated the Administrative Procedures Act when it wrote a rule expanding access to association health plans.

Association health plans allow small businesses and other groups to band together to buy health insurance. The rule allows more groups to join together to form associations.

The move is part of a broader Trump administration effort to open up skimpier, cheaper plans as an alternative to ObamaCare plans.