Although Affordable Care Act (ACA) marketplaces were beginning to stabilize in 2017, policy uncertainty stemming from a potential repeal of the law, threats to cost-sharing reduction reimbursements, and questions about enforcement of the individual mandate led many insurers to re-evaluate participation for 2018. In this report, we examine six states that faced the prospect of counties without a single insurer for 2018: Iowa, Nevada, Ohio, Oklahoma, Tennessee, and Washington. Interviews with regulators and insurers offer insight into how a set of diverse states sought to preserve coverage options for consumers in the wake of considerable instability in federal policy.