Supreme Court precedent on "severability," Kavanaugh said, is "fairly clear" and Congress did not use that same language in crafting the law to make the individual mandate "inseverable."
Justice Clarence Thomas, meanwhile, questioned whether Texas even had an injury to bring in its lawsuit.
"I think we're shadowboxing a bit here," he told Kyle Hawkins, the Solicitor General for Texas. Thomas asked what the injury was to the state if the fine as an enforcement mechanism for the individual mandate was zero.
The law was left in place by Congress and is still "functioning perfectly well," argued Mongan.
Without a penalty for non-compliance, the ACA "still presents a choice" that is constitutional, he said, a choice of "either buy insurance, or do nothing."
There have been other legal challenges to the ACA or to the Obama administration's enforcement of it-including the court case of the Little Sisters of the Poor against the HHS contraceptive mandate.
The ACA had required coverage of preventive services in health plans, and the Obama administration interpreted this to include all FDA-approved contraceptives, including Plan B emergency contraceptives which can cause early abortions.
When the administration crafted an "accommodation" for non-profits with moral objections to the mandate many of them still sued; they argued that the process offered by the administration to comply with the rule still forced them to essentially give the government a "permission slip" to provide contraceptive coverage in employee health plans.
The U.S. bishops' conference (USCCB) supported many of the law's goals, including expansion of health coverage for the uninsured, but ultimately opposed its enactment in 2010. The USCCB warned that the law would set up taxpayer funding streams for abortion coverage and did not include sufficient health coverage for immigrants.
However, the Catholic Health Association (CHA) strongly supported the law despite the objections of the U.S. bishops. The CHA filed an amicus brief at the Supreme Court in the new case, saying that the law "has made strides" towards increasing affordable health coverage for millions of Americans and decreasing the burden on hospital emergency rooms of caring for the uninsured.