One of the Affordable Care Act’s most prominent supporters is raising alarms about the future of the landmark health law.

Minnesota Gov. Mark Dayton, who pushed hard for fully implementing all of the provisions of the ACA in his state, including the expansion of Medicaid, says the law needs major fixes because it is no longer fulfilling its promise.

"The reality is the Affordable Care Act is no longer affordable for increasing numbers of people," he says.

Dayton was in large part responding to major premium increases slated for individual health plans offered on the Minnesota ACA marketplace, which is one of 17 state-run exchanges.

Although those buying ACA plans in the Gopher State benefited from some of the lowest rates in the first two years of the law’s implementation, they have since seen some of the largest rate hikes as the revenue provided by the low premiums proved woefully insufficient for insurers attempting to turn a profit.

Like many other exchanges, Minnesota is desperately trying to prevent insurers from fleeing its marketplace. The state’s largest insurer, however, Minnesota Blue Cross Blue Shield, has stopped participating.

Dayton’s comments are among a number of public acknowledgements from Democrats in recent months that the future of the ACA is in peril. The Obama administration has signaled that the next president will have to work with Congress to make changes to the law if it hopes to protect the gains in insurance coverage that it has led to.