The state’s decision not to expand Medicaid under the Affordable Care Act will push more than 400,000 Georgians into a coverage gap in which they don’t qualify for Medicaid but also can’t afford to buy private health insurance, a new report said Wednesday.

The Kaiser Family Foundation’s report is less revelation than confirmation of what experts in the state have predicted. But it underscores that, for a large group in Georgia, Obamacare will have little meaning.

“The problem is that some of these individuals are going to need health care and they are going to continue to wind up in emergency rooms and at physicians’ offices with no way to pay for the care that they need,” said Bill Custer, a health care expert at Georgia State University.

“That care will continue to be paid for by local taxpayers and by people who do buy health insurance and pay for health care.”

The health care law sought to provide health insurance to nearly all the 49 million Americans who don’t have it. The law envisioned that the lowest-income people would go onto a massively expanded Medicaid program; moderate-income people with no insurance would shop on the Health Insurance Marketplace and, in many cases, qualify for a federal tax credit.

The Supreme Court ruled last year, however, that the federal government may not compel states to expand Medicaid. Twenty-six states opted out, and one of the pillars of Obamacare dissolved for half the country. As a result, people who earn between 100 percent and 400 percent of the federal poverty level can shop on the new insurance marketplace and potentially qualify for a federal subsidy. But people who earn less than 100 percent of the poverty level can’t, because the law assumed they would go on Medicaid.

More than 5 million people in the states that have declined to expand Medicaid will fall into the resulting coverage gap, Kaiser’s report said, with the greatest numbers in Texas, Florida and Georgia.

Rachel Garfield, senior researcher with the Kaiser Family Foundation, said the study’s goal was “to put a number on something people have been talking about for a long time: who’s falling through the cracks?”

Garfield said that 31 percent of the state’s uninsured adults would fall into the coverage gap.

The Kaiser Family Foundation, a respected source of independent information on health care, is not connected to Kaiser Permanente, the insurer.

Custer, at Georgia State, has been using state-level census data to study the state’s uninsured population. He has concluded that the Medicaid decision here will result in 400,000 to 500,000 being pushed into the coverage gap.

The federal government will pay 100 percent of the cost of the Medicaid expansion for three years, decreasing to 90 percent in later years. Gov. Nathan Deal maintains the longer-term costs to the state would be untenable.