A coalition of Republican state attorneys general and governors are challenging the constitutionality of the Affordable Care Act in court, including the law’s provisions requiring insurers to cover people with preexisting conditions without raising rates

An analysis shows that many of these states have the highest proportion of such residents. Nine of the 11 states with the highest rates of preexisting conditions among adults under 65 have signed onto the lawsuit to strike down the ACA, according to data from insurance companies and the U.S. Centers for Disease Control and Prevention. The 2015 data, the most recent available, were analyzed by the Kaiser Family Foundation in 2016. (Kaiser Health News, which produces California Healthline, is an editorially independent program of the foundation.)

In California, more than 5 million adults have preexisting conditions, the data show. Many of them are among the 1.5 million people who purchase policies through the state exchange, Covered California. Existing state rules would protect people with preexisting conditions for 12 months if the ACA were struck down.

California Attorney General Xavier Becerra is leading the defense of the ACA in this case, joined by 16 other Democratic attorneys general.

For more, read Harriet Rowan’s coverage.