Advocates of Obamacare warned Tuesday that New Hampshire’s health care system will fall into chaos if the U.S. Supreme Court, which heard a challenge to the Affordable Care Act on Tuesday, renders it unconstitutional.

Nearly 8% of New Hampshire residents — about 104,900 people — obtain health care coverage from the two main pillars of the law — Medicaid expansion (63,100) and the healthcare.gov marketplace (41,772), according to state data.

“I can’t underscore this enough. In the middle of a pandemic this is the worst time to jeopardize the Affordable Care Act,” said state Sen. Tom Sherman, D-Rye, who is a physician. He said the ACA has especially proved critical in funding coverage for people with mental illness and substance abuse problems.

Sherman spoke during a press teleconference put on by Protect Our Care NH.

Sherman said the ACA is working, noting that rates for New Hampshire residents who purchase insurance in the ACA marketplace are expected to drop substantially next year.

Anthem will cut its rates an average of 15%, and Harvard-Pilgrim by 14%. The state’s third insurer, Ambetter/Celtic, is anticipating a smaller drop of 4%.

The current challenge of Obamacare is the third to go before the Supreme Court. This one focuses on whether the individual mandate remained constitutional once Congress removed the penalty, said Lucy Hodder, director of the UNH Law School Institute for Health Policy and Practice.

Twenty-one states, led by Texas, are challenging the law. New Hampshire officials filed a brief with the court supporting it, Hodder said.

“New Hampshire filed a brief that basically said if this law is overturned our health care system will be in chaos,” Hodder said.

Hodder said the ACA also guarantees coverage for pre-existing conditions, coverage for adults under the age of 26 on parental plans, and coverage for preventive care that is not subject to deductible and copays. Those coverages would also be threatened by an adverse ruling, she said.

Over the last six years, New Hampshire spent $77.7 million in state dollars on Medicaid expansion, which leveraged $2.29 billion in federal funds for the program, according to Hodder, who cited data from the New Hampshire treasury.

“This is politics, pure and simple,” said U.S. Rep. Chris Pappas, D-N.H., about the court challenge.