The White House declined to comment.
Administration officials say they are confident the entire law will be upheld by the Supreme Court, and there's no contingency planning to address whether all or parts of it are struck down. Sharp questioning by the court's conservative justices during public arguments has led many to speculate that at least some parts of the law will be struck down.
Opponents of the law argue that Congress overstepped its constitutional authority by requiring most Americans to have health insurance, starting in 2014. The administration says the mandate is permissible because it serves to regulate interstate commerce, underpinning another provision of the law that requires insurance companies to accept people in poor health. A decision is expected by early summer.
Former officials say it's likely that some form of high-level assessment and planning is going on within the administration. It has happened in the recent past.
Last year, when the GOP-led House threatened to block funding for carrying out Obama's law, Health and Human Services Secretary Kathleen Sebelius wrote to Congress outlining potential consequences. She said the administration might have to suspend payments to Medicare Advantage plans, popular private insurance alternatives that cover about one-fourth of all beneficiaries. That would have sent millions of seniors back into traditional Medicare, scrambling to find new doctors and coping with higher out-of-pocket costs.
Scully dismissed the notion that private Medicare plans would be jeopardized if the Supreme Court throws out the law.
"The idea that Medicare Advantage plans would shut down and patients would be thrown into the street is just people making up arguments to stir the pot," he said.
Repeal of the law would also mean that seniors would lose some new benefits, including the closing of the prescription coverage gap called the "doughnut hole," and no-charge preventive services such as an annual wellness physical.
"There is no doubt that striking down (the) Medicare provisions would be enormously disruptive for patients, physicians, hospitals and countless other providers and suppliers," said Rep. Sander Levin, D-Mich., ranking Democrat on the House Ways and Means Committee, which oversees the program.