Health law backers say the GOP is exaggerating the changes, but that doesn’t mean some aren’t worrying about whether it’s been too watered down. Tim Jost, a well-known health lawyer who backs the law, said the vagueness of some exemptions troubles him.

“Can I say, ‘I don’t like the options available,’ or ‘I’d rather spend my money on whatever,’” he said. “I just don’t understand where they are going with these very wide-open hardship exemptions, and I think they are opening the door to some real mischief.”

Insurers, which priced their policies based on the expectation that the mandate will drive otherwise reluctant (and relatively healthy) people into their plans, are watching closely for any further erosion. Premiums could soar without healthy customers to balance the cost of covering sicker people with pre-existing conditions, now required by law.