The Supreme Court announced yesterday that it will rule on the constitutionality of the President’s health care reform act, allotting a lengthy five and a half hours for oral argument, more than five times the length of a normal hearing. The event is expected to take place in March 2012, and while a number of legal issues will be addressed, the most important is the individual mandate, the piece of the law that requires every American to purchase health insurance or pay a fine. At the heart of the debate will be one question: What are the limits to Congress’s authority under the Commerce Clause? Defendants have, up to this point, struggled to find a persuasive answer. While lower courts have been split on the final ruling — some have upheld the mandate, others have not — the Supreme Court will likely require an airtight answer in order to rule in the mandate’s favor.