Former US President Bill Clinton says President Barack Obama should find a way to let Americans keep their health coverage under Obamacare.
Insurance companies have cancelled numerous policies that do not meet the law's strict requirements, even though Mr Obama initially pledged otherwise.
Mr Clinton said his fellow Democrat should "honour" his commitment, even if it means changing the law.
Republicans seized on Mr Clinton's comments.
In addition to the cancelled insurance policies, the federal website established under the law - which allows consumers to shop for private health insurance plans - has been plagued by glitches.
Mr Clinton campaigned for the Affordable Care Act, but now he is the latest politician to speak out against it.
'Big lesson'
"I personally believe, even if it takes a change in the law, that the president should honour the commitment the federal government made to those people and let them keep what they've got," Mr Clinton said in an interview published on Tuesday.
The former president - who is a Democrat, like Mr Obama - did reaffirm his support for the healthcare law, though, saying: "The big lesson is we're better off with this programme than we are without it."
His comments come just days after Mr Obama apologised to those people whose policies have been cancelled under Obamacare.
"I am sorry that they are finding themselves in this situation based on assurances they got from me," he said in an interview with NBC News on 8 November.
"We didn't do a good enough job in terms of how we crafted the law," he added.
"We've got to work hard to make sure that they know we hear them, and we are going to do everything we can to deal with folks who find themselves in a tough position as a consequence of this."
