Debate over the national healthcare law headed for the U.S. Supreme Court Monday, the first of three days of arguments on its constitutionality. The first argument Monday centers on the Anti-Injunction Act. The 1867 measure bars suits against the federal government regarding a \"tax\" until the tax actually goes into effect and someone actually is required to pay it. The main provision of the Affordable Care Act being challenged -- the requirement that everyone who can afford it obtain insurance or else pay a fine -- does not go into effect until 2014. If the act bans the current court case, it would be 2015 before the constitutionality of the individual mandate could be thrashed out in the courts. On Day 2 of argument, Tuesday, the justices hear the two-hour debate regarding the individual mandate. The thrust of the argument is whether the individual mandate exceeds congressional power outlined in Article I of the Constitution. The requirement that most individuals get health insurance -- those who can afford it -- \"is a valid exercise of Congress\' commerce power,\" the administration said in a brief to the high court. On Day 3 of the argument, Wednesday, the justices will hear the 90-minute debate on whether the individual mandate can be \"severed\" from the rest of the law. In other words, if they strike down the mandate, does the rest of the law go down with it. Also Wednesday, the justices hear 60 minutes of argument on the healthcare law\'s expansion of Medicaid, the joint federal-state program that provides health care for the poor. In a brief, the 26 states challenging the law said the states want to know if Congress exceeds \"its enumerated powers [in the Constitution] and violates basic principles of federalism when it coerces states into accepting onerous conditions that it could not impose directly by threatening to withhold all federal funding under the single largest grant-in-aid program [Medicaid]?\" Any threat of a Medicaid cutoff is serious. Medicaid -- for which states provide about half the funding -- accounts for more than 40 percent of all federal funds dispersed to states -- $251 billion in 2009 alone -- and approximately 7 percent of all federal spending.