President Barack Obama's main idea for getting quality healthcare at less cost was in jeopardy Wednesday after key medical providers called his administration's initial blueprint so complex it's unworkable. Just over a month ago, the administration released long-awaited draft regulations for "accountable care organizations," networks of doctors and hospitals that would collaborate to keep Medicare patients healthier and share in the savings with taxpayers. Obama's healthcare overhaul law envisioned quickly setting up hundreds of such networks around the county to lead a bottom-up reform of America's bloated healthcare system. But in an unusual rebuke, an umbrella group representing premier organizations such as the Mayo Clinic wrote the administration Wednesday saying that more than 90 percent of its members would not participate, because the rules as written are so onerous it would be nearly impossible for them to succeed. "It's not just a simple tweak, it's a significant change that needs to be made," said Donald Fisher, president of the American Medical Group Association