A couple of hundred people rallied outside the state Capitol building Monday afternoon, calling on Gov. Nathan Deal to expand Medicaid — a key provision of the Affordable Care Act.

The NAACP and other liberal groups staged the “Moral Monday” rally, an offshoot of a movement that started in North Carolina. One of the group’s goals is to promote Medicaid expansion in Georgia.

“Nathan Deal is turning his back on 650,000 people who could have health care,” state Sen. Vincent Fort, D-Atlanta, told the crowd. “If Nathan Deal gets sick tomorrow, he will be at the hospital in an hour. What about the 650,000 men, women and children who don’t have health care coverage?”

Expanding Medicaid would extend health coverage to an additional 650,000 low-income Georgians. Deal has said the state can’t afford to expand a program that’s already overtaxed and too costly. Twenty-two other states have also rejected Medicaid expansion, while half of the states and the District of Columbia are moving forward with it.

Deal has estimated the expansion would cost the state $4 billion over a decade, but supporters of the health care law say the cost would likely be closer to half of that. They also argue Georgia can’t afford to turn away more than $30 billion over that same time period in new federal dollars that would flood into the state if it expanded the health program.

The governor and other opponents of the law have questioned whether the debt-ridden federal government will be able to hold up its end of the deal. Under the Affordable Care Act, the federal government pays for the full cost of newly eligible Medicaid recipients under expansion for the first three years. Its share then drops to no lower than 90 percent of the cost.

Medicaid has its problems, but expansion would at least be a start to helping improve access to care, said Cathryn Marchman of Saint Joseph’s Mercy Care Services. The nonprofit sees nearly 13,000 patients in Atlanta each year, 92 percent of whom are uninsured.

“We can’t continue to sustain care for the poor on grants alone,” said Marchman, who attended Monday’s rally. “Expansion would empower patients to take care of their health care.”