Following the adoption of the Affordable Care Act, Wyoming’s Northern Arapahoe tribal members signed up in high numbers for fully subsidized health insurance, many of whom had never received any before.

Now, a federal judge in Casper says it’s not the responsibility of the federal government to pay for tribal health care. It’s the responsibly of the tribe. U.S. District Judge Scott Skavdahl ruled against the tribe in its lawsuit with the IRS, arguing that under the ACA the Northern Arapaho tribe qualifies as a large employer.

But Northern Arapaho chairman Dean Goggles says, by treaty, the federal government is responsible to pay for Native American health care. He says the tribe plans to keep fighting.

“We are working hard to improve health care for tribal members and to get more of our people on into health insurance. We will continue to work with other tribes across the nation to fix the problem.”

High rates of heart disease and diabetes on the Wind River Indian Reservation has led to a life expectancy there of only 51 years.

Goggles says the tribe will consider an appeal in coming weeks.