An unprecedented three days of oral arguments before the US Supreme Court debating the constitutionality of key aspects of President Obama’s Affordable Care Act concluded on Wednesday, in a case that throws into sharp relief the division between the conservative and liberal Justices. The portion of Obamacare at issue mandates that, beginning in 2014, nearly every American must either purchase health care insurance, or be subject to a penalty on his or her tax return.

Twenty-six states have attacked this mandate, contending that it is unconstitutional for Congress to compel an uninsured person to purchase a product on the private market. Proponents of this universal health care plan argue that it is well within Congress’ power to regulate interstate commerce, and that the uninsured’s inevitable consumption of the health care services that helped create the nationwide problem of unaffordable premiums place this issue well within the purview of Congress’ power.

More than one hundred twenty-five briefs have been filed regarding this landmark case, and the Justices entertained six hours of oral arguments -- three times that of normal cases -- to thoroughly understand each side’s stance. While the conservative Justices may see this case as an opportunity to harness overextended federal power and prevent its encroachment on state authority, the liberal side doesn’t consider this mandate to be pushing the limits on Congress’ authority by any means.

Congress’ power to regulate commerce harkens from Article I, section 8 of the US Constitution, and may be grouped into three categories: the channels of interstate commerce, the instrumentalities of interstate commerce and activities that have a substantial impact on interstate commerce. While interstate commerce was originally defined as that business which took place across state lines, modern interpretations of constitutional law allow for any economic activities that substantially impact interstate commerce to be included. This substantial impact test was set forth in 1942 in Wickard v. Filburn, a case involving wheat sales that allowed for the possibility that even economic activity occurring intrastate could impact the interstate economy.

In keeping with the Wickard logic, proponents of the health insurance mandate argue that, just as interstate purchases of goods can impact the economy, the lack of purchase may similarly have a substantial effect. Specifically, by not purchasing health care, uninsured individuals are impacting those with insurance within the state who are forced to offset the cost to the individuals supported by the state’s health systems. This intrastate impact has interstate consequences and, therefore, gives Congress the right to regulate this activity.

Opponents fear the slippery slope of granting Congress this power over what is arguably a solely intrastate activity. Insurance policies are specific to each state, and are thought to fall solely under individual state jurisdiction. If this state-specific issue is seen as having interstate impacts, where does it end? In this globalized economy, doesn’t every economic activity in some way impact the national economy at large?

In US v. Lopez, a student brought a gun to school in violation of the Gun-Free School Zones Act. While this isolated incident occurred in the singular state of Texas, the argument was made that the broader consequences of this action were on a national scale. Bringing a gun on school grounds could negatively affect education, lead to violent crime and raise insurance rates, thereby affecting the national economy at large.

The Supreme Court shot this argument down, however, setting limits for Congress’ power under the Commerce Clause. Obamacare opponents fear that a verdict upholding the constitutionality of the insurance mandate could undermine the boundaries set in Lopez.

The Supreme Court is set to hand down a decision this June. It is unclear whether a holding of unconstitutionality would invalidate the entire law -- with its hundreds of unrelated provisions -- or simply nullify the mandate that Americans purchase health insurance.