The Obama administration last week announced a big increase in support for community health centers in the latest expansion of a program that has a long bipartisan history and robust bipartisan support today.

The health centers got a start under President Lyndon Johnson’s war on poverty, expanded slowly over the years, and then got a huge lift from President George W. Bush, who doubled federal financing for the centers over five years and created or expanded almost 1,300 clinics in medically underserved areas. He admired the cost-effectiveness of the nonprofit centers, which treat low-income people and recent immigrants in poor urban neighborhoods and isolated rural areas and serve patients who would otherwise seek more expensive care in emergency rooms or hospitals.

The 2010 Affordable Care Act further expanded the program with increased funding over a five-year period, and the larger system of clinics is one of health care reform’s most praiseworthy achievements.

Today the health centers have become the largest primary care system in the United States. They serve some 23 million patients a year in over 9,000 locations across the country. Their professional association says they save the health care system some $24 billion a year by providing timely treatment and preventive care designed to meet local needs and preferences. The government says their quality of care equals and often surpasses that delivered by other primary care providers.

Last week the Department of Health and Human Services announced that it would distribute $169 million provided by the Affordable Care Act to open 266 new health centers in 46 states, the District of Columbia and Puerto Rico. That is on top of more than 700 new health centers that have already opened as a result of the A.C.A. They were all financed by a trust fund that could not be touched for five years and by annual discretionary appropriations that can be cut at any time.

The trust fund and a related trust fund for the National Health Service Corps that supplies most of the doctors and other health professionals who serve in the community health centers were set to expire after their five-year run at the end of September.

Fortunately, in the spring, Congress by overwhelming margins extended funding for the centers and health service corps for another two years as part of legislation notable mainly for fixing a flawed Medicare payment formula for doctors and extending an important children’s health insurance program. This will keep the program safe through the 2017 fiscal year but it will need to be nurtured in the years beyond.