CHICAGO -- President Barack Obama pushed hard Monday for a health care overhaul, saying the system is "a ticking bomb" for the budget that could force America to "go the way of GM" without a legislative fix. 

Obama went before the American Medical Association in Chicago to declare anew that the existing system leaves too many uninsured and forces "excessive defensive medicine" by doctors worried about malpractice suits. He also declared once again that he does not favor socialized medicine and cautioned people to beware of "scare tactics and fear-mongering" by critics who make this claim. 

Obama did tell his audience of physicians and health care professionals that he's "open" to requiring all Americans to have health insurance, while stressing that the plan would permit continuing assistance for those who cannot afford it on their own. 

Obama said that a "health care exchange" would be set up to provide additional options for the uninsured. 

"A big part of what led General Motors and Chrysler into trouble," he said, "were the huge costs they racked up providing health care for their workers -- costs that made them less profitable and less competitive with automakers around the world." 

"If we do not fix our health care system," Obama said, "America may go the way of GM -- paying more, getting less, and going broke." 

Obama also said the nation must explore ways to reduce the number of unnecessary medical tests or procedures that sometimes are conducted to stave off possible malpractice lawsuits. 

And Obama said that placing caps on malpractice awards, which many doctors want, would be unfair to patients, a statement that produced a loud boo from the audience. 

However, he said, "we need to explore a range of ideas about how to put patient safety first, let doctors focus on practicing medicine, and encourage broader use of evidence-based guidelines. That's how we can scale back the excessive defensive medicine reinforcing our current system of more treatment rather than better care."