The health care law of the land has survived for now, but it needs help — and it needs it soon.

Soaring prices and fewer choices may greet customers when they return to the Affordable Care Act's insurance marketplaces this fall, in part because insurers are facing deep uncertainty about whether the Trump administration will continue to make key subsidy payments and enforce other parts of the existing law that help control prices.

Assurances don't look to be coming anytime soon. "As I said from the beginning, let ObamaCare implode, then deal. Watch!" President Donald Trump tweeted early Friday,...