Medical-insurance markets crafted by four U.S. Republican governors won conditional approval by the Obama administration as the federal government nudges states toward full implementation of the landmark health-care overhaul.

Idaho, New Mexico, Nevada and Utah are set to meet Affordable Care Act rules for marketplaces where residents can buy insurance, the U.S. Health and Human Services Department said in a statement today. The agency also approved plans in Democratic-led California, Hawaii and Vermont, bringing to 18 the number of states scheduled to run exchanges on Jan. 1, 2014.

“In all of these states there's more work to be done to be ready for open enrollment in October, but we believe they've made significant progress,” said Gary Cohen, director of the department's Center for Consumer Information and Insurance Oversight, on a conference call with reporters.