On Tuesday, U.S. District Judge Gladys Kessler, of the District of Columbia, became the third federal judge to uphold the constitutionality of the new health-care law’s requirement that Americans purchase health insurance or pay a penalty. Two federal judges have ruled against the constitutionality of the mandate, including Roger Vinson, who struck down the entire law earlier this month. Wendy Parmet, Matthews Distinguished Professor of law at Northeastern University, assesses the debate.

Is the so-called “individual mandate” constitutional?

Yes, under settled law. If we understand the relationship between the federal and state government in the way that’s been understood for much of our constitutional history, and certainly since the New Deal, then there’s ample federal authority for the government to impose a tax penalty on Americans who fail to have health insurance. But we also have to understand that the perceived power of the federal government has waxed and waned over the course of our history. It is always possible that the relationship may be changing again. Although precedent supports the mandate, two judges have found it to be unconstitutional, and it is certainly possible that the Supreme Court will do likewise.

Democratic presidents appointed thethree judges who ruled in favor of the law, but Republican presidents appointed the two judges who ruled against the law. Are personal politics getting in the way of sound decision-making?

This is a deeply divisive ideological issue. It’s almost impossible for a judge’s world view not to affect his or her perception of the issues at stake. Having said that, I wouldn’t say the judges are necessarily acting in a partisan manner. In some ways, this decision depends on perceptions of the role of the federal government over which the parties, and many Americans, are deeply divided. So, it’s not surprising that we’re seeing Democratic judges rule one way and Republican judges rule in the opposite direction.

Judge Vinson writes that the commerce clause of the Constitution prevents Congress from legally requiring individuals to purchase health insurance. On the other hand, the Obama administration says it has the power to enact the individual mandate in order to regulate interstate commerce in health care. Who’s correct?

The Constitution gives the federal government broad, plenary power to regulate interstate commerce. In addition, the Constitution gives the federal government the authority to enact laws that are “necessary and proper” to support Congress’ power under the commerce clause. Health insurance is undoubtedly interstate commerce and the so-called mandate is without question both a regulation of interstate commerce and a law that is necessary and proper to support a regulation of interstate commerce. From that perspective, the federal government clearly has the power to enforce the mandate. Opponents of the law argue, however, that the federal government can only regulate activity with regards to interstate commerce, not inactivity. Since not buying insurance is inactivity, the provision is invalid. Interestingly, the Constitution’s text does not distinguish activity from inactivity. Still, the distinction has had a powerful resonance with at least two judges and many of the act’s opponents. Ultimately the Supreme Court will have to decide whether the mandate survives as a regulation of interstate commerce, or whether Congress’ power is limited by this activity/inactivity distinction.