California’s Medicaid-eligible rolls are swelling as part of a nationwide expansion of the program under the Affordable Care Act, a finding that should give other states’ Medicaid agencies pause over the coming year.

Nearly 3 million new people have joined Medi-Cal over the past few months, bringing Medi-Cal enrollment to 12 million and making the state the largest healthcare buyer in the country, according to published reports. California’s Medicaid population now represents 17% of the nation’s total enrollment. Nearly one in three state residents is now a Medi-Cal recipient.

State lawmakers this week said the latest enrollment news is alarming, and that even if a new pending rate request hike goes through, there is concern the state will run out of funding to care for its Medicaid recipients. State Medicaid costs are up 4.3% this year while federal share of costs for new enrollees will begin dropping in 2016, according to Gov. Jerry Brown (D). There are mounting concerns there will not be enough plan doctors to accommodate the enrollment surge. One recent study found that only 57% of the state’s primary care doctors accept new Medi-Cal patients.

“Medi-Cal is turning into an empty promise with an insurance card,” said Molly Weedn, a spokesman for We Care for California, a coalition of doctors, hospitals, health plans and labor unions pushing for higher payment rates, told the Associated Press.

Even red states are doing an about-face now on sharp criticism of the ACA, and are taking steps to expand their struggling Medicaid programs. Republican lawmakers in Tennessee, Kansas, Indiana, Utah and others are exploiting the Affordable Care act to draw upon federal dollars and expand the Medicaid program, a notion the long-term care industry fears will sap much-needed funding in the coming years. Some observers say the efforts couldn’t come at a worse time, as huge swaths of aging boomers are expected to enter the system in need of long-term care for chronic health issues.