Saying health care coverage for millions of Americans is at risk, Sen. Jon Tester this week cosponsored legislation to allow the Senate to defend the Affordable Care Act in court.

Last month, Judge Reed O'Conner with the Federal District Court in Fort Worth, Texas, struck down the Affordable Care Act as unconstitutional.

It wasn't the first attack on the ACA, which provides insurance to nearly one in 10 Montanans and tens of millions of Americans. It also ensures affordable coverage for one in two non-elderly citizens with a pre-existing condition.

“A bunch of unelected bureaucrats have decided to rewrite the law of the land and threaten the health and safety of thousands of Montanans,” Tester said in a statement. “If they won’t protect Montanans, then we will.”

Last June, the Department of Justice under President Donald Trump also announced that it would stop defending key parts of the ACA, including that which prohibits insurance companies from withholding health care coverage due to a preexisting condition.

That was followed in December by the District Court ruling in Texas. Tester said that decision puts many critical parts of the ACA at risk, including mandatory coverage of essential benefits, a prohibition on lifetime caps, and the guarantee that children can stay on their parents’ insurance until the age of 26.

“If they won’t defend the law then we will,” Tester said. “Montanans are paying way too much for health care. Washington needs to stop attacking the health and well-being of families and instead work to lower health insurance premiums.”

The proposed legislation would authorize the Senate Legal Counsel to intervene in the lawsuit and defend those who rely the ACA to access insurance. Tester also has introduced legislation to lower the cost of prescription drugs and expand access to health care.