With President Obama trying to quell a rebellion among Democrats by proposing his own administrative fix to Obamacare, foes of the law took to Twitter today to demand what authority the President has to unilaterally change his law by “fiat,” as at least one critic put it.

The Obama “fix” to the law allows insurance companies to continue current policies for a year. What is the legal basis for this, given that the Affordable Care Act stipulates minimum standards for health coverage?

I put the question to the Obama administration. Here’s the answer, from a spokesperson for the Department of Health and Human Services:

“The Supreme Court held more than 25 years ago that agencies charged with administering statues have inherent authority to exercise discretion to ensure that their statutes are enforced in a manner that achieves statutory goals and are consistent with other administrative policies. Agencies may exercise this discretion in appropriate circumstances, including when implementing new or different regulatory regimes, and to ensure that transitional periods do not result in undue hardship.”

The Supreme Court case in question, HHS says, is Heckler v. Chaney in 1985. That case involved a lawsuit brought by inmates who were sentenced to death by states. They sued to force the FDA to take action to block the use of certain drugs in state lethal injections, on the theory that the FDA has no authority to approve this use of the drugs. But the Court ruled that private citizens cannot force a federal agency to bring an enforcement action, even one in keeping with federal statutes.

David Vladeck, an expert in administrative law at Georgetown Law, tells me that critics would likely point out that the specifics of the case are not parallel to the current argument over the Affordable Care Act.  “The inevitable question will be, what does lethal injection have to do with the health law?” Vladeck said.

But Vladeck clarified that the larger finding of the Court in that case does in fact support the administration’s reading of administrative law.

“The ultimate conclusion of the Court was that when it comes to using the various tools an agency has, it has very broad discretion, including refraining from enforcement actions, if the agency thinks this it will achieve its statutory goals,” said Vladeck, who was a political appointee to the FTC during Obama’s first term, but is widely quoted as an independent expert on these topics.

“The President does have discretion not to take enforcement action when he believes it would frustrate the purpose of federal law,” Vladeck added.

Vladeck said the problems with the health law had created a rare set of administrative and legal conundrums that virtually ensured that the legal rationale for a fix would appear odd at first glance.

“The administration is put in a position where they have to use what seems like an odd justification to delay the president’s signature achievement,” Vladeck concluded. “But I think they’re being responsible in doing it, and the legal case for it is solid.”

Critics of the law, one imagines, will not deem this persuasive. But there’s the rationale.