Paul D. Clement, who represents the 26 states suing to overturn the Patient Protection and Affordable Care Act, argued in the third day of argument before the high court the rest of the provisions of the law are too "interconnected" to the mandate to stand on their own.
The court also considered whether the act's expansion of Medicaid is coercive to the states.
On Monday and Tuesday, the justices heard argument on whether they can even take any action before the law is fully effective and whether the provision that requires individuals to buy health insurance is constitutional.
Justice Elena Kagan asked Wednesday if it wouldn't be better to take "half a loaf," meaning preserve part of the law, than to throw the whole law out.
"Well, Justice Kagan, I think there are situations where half a loaf are actually worse," Clement responded.
The justices also noted a number of provisions of the act have nothing to do with healthcare reform. Rather, they are reauthorizations of older programs that were included in the act as a matter of convenience.
Deputy Solicitor General Edwin Kneedler argued there's no reason to scrap the entire law and, should the mandate be declared unconstitutional, it would be up to Congress to fix the rest of the statute.
On the issue of Medicaid expansion and whether the federal government has the power to force states to make Medicaid available to more people, Kneedler argued Congress has "done it many times" and the court shouldn't get bogged down in the financial aspects of the law.
In arguing against the expansion of Medicaid, Clement said the healthcare reform law coerces the states into expanding the program by threatening to withdraw all Medicaid funds if more people aren't allowed to participate.
Justice Stephen Beyer, however, maintained such a reading of the law is unreasonable and such action would violate the Administrative Procedure Act.
"What's telling here, though, is 26 states, who think that this is a bad deal for them, actually are also saying that they have no choice but to take this because they can't afford to have their entire participation in this 45-year-old program wiped out," Clement said.
Justice Antonin Scalia then needled Clement a bit, asking if perchance the governors of the 26 states are all Republicans.
"There's a correlation," Clement responded to laughter in the courtroom.
Health insurers fear if the mandate is struck down but the rest of the law survives, they would be forced to accept millions more sick customers without enough new healthy customers to balance out the risk pool.