California’s Obamacare exchange scrubbed its annual rate announcement this week, the latest sign of how the ongoing political drama over the Affordable Care Act is roiling insurance markets nationwide. The exchange, Covered California, might not wrap up negotiations with insurers and announce 2018 premiums for its 1.4 million customers until mid-August — about a month later than usual. Similar scenarios are playing out across the country as state officials and insurers demand clarity on health care rules and funding, with deadlines fast approaching for the start of open enrollment this fall. “It’s insane,” said John Baackes, CEO of L.A. Care Health Plan, which has about 26,000 customers on the California exchange. “Here we are in the middle of July and we don’t even know what rules we will be operating under for open enrollment.