The Trump administration is arguing in court that the ACA's protections for people with pre-existing conditions should be thrown out.
justsecurity.org/wp-content/upl…

The Justice Department's brief creates another cloud of uncertainty for insurers, just as they're filing proposed ACA rates for 2019. When insurance companies face uncertainty, they increase premiums.

This ACA legal case will likely not be decided soon, so I wouldn't expect insurers to drop out of the market. Ultimately, either the ACA will remain intact. Or, it will get blown up by the courts, at which point insurers and regulators will have to start from scratch.

27% of non-elderly adults have pre-existing conditions. Arguing in court that protections for them should be eliminated, as the Trump administration is now doing, could provoke a backlash in an election year.
kff.org/health-reform/…

For all legal issues about the ACA and this case, certainly follow @nicholas_bagley.

Repealing the ACA's individual mandate penalty poses trade-offs, but no doubt was a popular move. Ending protections for people with pre-existing conditions, as the Trump administration is now arguing, would be quite the opposite.

The ACA requirements that the Trump administration is asking a court to throw out:
Guaranteed issue, which prevents insurers from denying coverage to people with pre-existing conditions.
Community rating, which prevents insurers from charging sick people more than healthy people.

27% of non-elderly adults have a pre-existing condition that would have led to a denial of insurance before the ACA. Many more have conditions that led to premium surcharges based on health.
kff.org/health-reform/…