LOS ANGELES — California was among the nation's first states to boldly endorse President Obama's federal health care law after it was adopted three years ago, and on Thursday relieved officials were among those breathing the loudest sigh of relief when the Supreme Court declined to strike it down.

The decision, health and insurance officials say, perfectly positions the state to add some 6 million residents to the ranks of the insured by the federal Affordable Care Act's 2014 deadline and, while there are some lingering questions about how to find and pay doctors to treat all of them, they expressed confidence that those details will be worked out with, among other things, billions of dollars in federal money.

"The passage of the Affordable Care Act is one of the most significant legislative achievements of the last 40 years," said state Insurance Commissioner Dave Jones.

Had the court's 5-4 decision gone the other way, Jones said, provisions of the federal Affordable Care Act that Califonria had already enacted could have been wiped out, including those allowing people to keep their children on their insurance policies until age 26 and the elimination of caps on how much money insurers must pay for medical care over the course of a person's lifetime.

The age 26 requirement currently benefits 350,000 young Californians, Jones said, while the elimination of caps benefits all 12 million insured Californians and has saved many peoples lives already by allowing them to continue to seek treatment for potentially fatal conditions. .

"I can't tell you how many Californians I have met who are alive today because of the elimination of the lifetime caps," he said.

Officials from the state's attorney general to the head of the Department of Health and Human Services to numerous lawmakers throughout the state hailed the decision, Health and Human Services Secretary Diana S. Dooley proclaiming Thursday "a very great day."

"California has been a leader in health care reform for a very long time," she said. "We've had many starts and stops and we are now in the full go mode."

The head of the California Medical Association, the state's largest doctors group, signaled a note of caution, however, questioning whether California can find the doctors to provide regular medical care to 6 million more people in the coming years, especially the 3 million he said are expected to be added to the rolls of MediCare and MediCal, government-subsidized programs for the elderly and poor.

"Generally, yes, we think most of what's in the Affordable Care Act is good for patients, but we still have major concerns about the fact that providing insurance to patients doesn't mean their going to have access to doctors because MediCal and MediCare programs are grossly underfunded," said Dr. James T. Hay, the association's president.

Jones acknowledged that budget constraints have made it difficult to expand those programs, but he said an additional $6 billion the state expects to receive now that the law has been upheld should make up for that. He said the availability of more preventive health care programs should also reduce the burden on hospital emergency rooms and clinics utilized by poor people.

"The good news is that in the Affordable Care Act there is additional funding and reimbursement for primary care physicians in particular," he said.

Hay expressed concerns the money wouldn't be sufficient to entice many more doctors to treat Medicare and MediCal patients and, that in the end, the federal funds may eventually run out.

Some have suggested using more physician assistants and nurse practitioners could bridge the gap in finding enough doctors to treat those added to the insurance roles.

Hay said his organization, which represents 35,000 doctors, supports that but only if a doctor remains in charge of a patient's care.

"Because we believe that patients want to have their medical care supervised by a physician, even if it's ultimately delivered by a nurse practitioner or a physician assistant," he said.