Georgia health insurance customers have a lot on the line with a court case the state has joined trying to repeal key parts of the Affordable Care Act.

The ACA, also known as Obamacare, requires every American to have health insurance. It also requires every health insurance company, among other things, to offer coverage regardless of customers’ pre-existing conditions, such as diabetes. A lawsuit that Georgia joined in February calls those requirements unconstitutional.

The Trump administration this week said it would not defend the law against the lawsuit.

Georgia Attorney General Chris Carr said the law constitutes “federal overreach.”

Other states are filling the administration’s role, banding together to defend the law and arguing against Georgia and 19 other states joined in the suit. Time will tell whether the lawsuit succeeds. But in the meantime, companies that insure Georgians are right now putting together their rate proposals for 2019.

About 480,000 Georgians have coverage purchased through the state’s ACA exchange.

Individual policy buyers in Georgia saw major rate hikes last year, with some premiums increasing by more than 50 percent. Companies and bond-rating agencies blamed uncertainty in the market due to Washington politics.

This lawsuit injects yet more uncertainty. If rates rise again, those costs will be spread across the individual customer market, no matter whether the person buying the insurance buys it on the exchange or off.

On the other hand, for opponents of the ACA the lawsuit holds out hope that the mandate will fall away and they can simply opt not to have insurance — or choose to buy insurance that covers less and is cheaper.

The ACA has survived several legal challenges. The most perilous was the first one, when the U.S. Supreme Court in a 5-4 decision said ruled that the mandate that every individual have insurance was constitutional because it is a tax.

However, at the urging of President Donald Trump, Congress last year repealed the financial penalty for violating the individual mandate. So, the lawsuit says, the mandate is no longer a tax, and thus it’s no longer constitutional.