One of the biggest threats to the success of President Obama's health care law comes from shortages of doctors, nurses and other health care professionals. But a 15-member commission created to investigate the problem has never met in two and a half years because it has no money from Congress or the administration. With an aging population and 30 million people expected to gain coverage under Mr. Obama's health care law, the demand for medical care is expected to increase. But Dr. Sheldon M. Retchin, the vice chairman of the panel, the National Health Care Workforce Commission, said, "We are prohibited from meeting and discussing these issues."