Conservative critics of the House health care proposal are questioning whether it passes constitutional muster, but some scholars are skeptical.

Sen. Rand Paul is advancing the argument by citing the reasoning of Chief Justice John G. Roberts Jr., who wrote the 2012 opinion in NFIB v. Sebelius for the Supreme Court when it upheld the individual mandate penalties in the 2010 health care overhaul law. The current House GOP proposal would partially repeal and replace that law.

“I think there is a potential constitutional question because you are penalizing people for not buying insurance. We had that whole debate in the court about an individual mandate,” the Kentucky Republican said. “They originally approved it because they said it was a tax.”

“But now we’re talking about a penalty to a private company. I think there are questions,” Paul said.

In his opinion in NFIB v. Sebelius, Roberts said the health care law essentially violated the Constitution’s Commerce Clause giving Congress the power to regulate interstate commerce because it forced people to buy health insurance. But he wrote the requirement that individuals pay a penalty for not obtaining health insurance “may be reasonably characterized as a tax.”

Several constitutional scholars expressed doubts about the likelihood of legal trouble with provisions providing for so-called penalty premiums to be charged to people who seek to purchase health insurance after a gap in their coverage.

“I am highly skeptical of Sen. Paul’s theory,” said Seattle University Associate Professor of Law Andrew Siegel, a former clerk to Justice John Paul Stevens.

“The objection to justifying the individual mandate on Commerce Clause grounds was that a voluntary commercial transaction or economic act was allegedly a predicate for regulation under the Commerce Clause,” Siegel said in an email. “While such a voluntary action was absent in NFIB, it is present here in the insurance purchase the previously uninsured person is now making.”

Thomas Miller, a resident fellow at the American Enterprise Institute who studies health policy, said that while the constitutional question is a “stretch,” there could be cause for a relatively small tweak in the language that is being considered by the House Energy and Commerce, and Ways and Means committees.

“The bill language might be adjusted [even post-markup], to ‘allow’ insurers to impose that additional premium ‘penalty’ rate instead,” Miller said. “There may be some uneasiness, procedurally, about appearing to regulate premiums differently though budget reconciliation.” The budget reconciliation process provides an easier path for consideration on the floors, but it mandates that the measures pertain largely to taxes, spending and budgetary matters.

Such a modification may be welcomed by conservatives in the House, who are exploring the constitutional questions among other issues with the bill moving through the committee process.

House Freedom Caucus Chairman Mark Meadows of North Carolina, noting he’s not an attorney or constitutional scholar, said House conservatives have discussed the possibility that the insurance penalty for not maintaining continuous coverage is unconstitutional and that they have someone looking into it.

Lindsey McPherson contributed to this report.