WASHINGTON — The mood was upbeat in early March when scores of powerful lawmakers and lobbyists joined President Obama in the East Room of the White House to talk about fixing the nation’s health care system. Still, Sen. Chuck Grassley, R-Iowa, rose to tell Obama that many Republicans had a problem with his plan to let the government compete with private insurers. ‘There’s a lot of us that feel that the government is an unfair competitor,’ Grassley said. ‘We have to keep what we have now strong, and make it stronger.’ Three months later, disagreement has turned to discord over a key element of Obama’s health care prescription: his insistence on a ‘public plan’ to compete with private insurers. America’s Health Insurance Plans, an industry trade group, is joined by the American Medical Association, U.S. Chamber of Commerce and others that have expressed misgivings about greater government involvement. ‘We’re not sure that the government is very good at running a health plan,’ said Nancy Nielsen, president of the AMA, which heard Obama defend his plan Monday. That has led to a number of compromise proposals, designed to inject choice and competition into the market without letting […]