previously all-white Central High School under the school board's attempt to follow the order of Brown. The tension became severe when Governor Faubus ordered the National Guard to prevent the nine from entering the school and President Eisenhower responded with federal troops to escort them. Five months after the integration crisis happened, the school board filed suit in the United States District Court of the Eastern District of Arkansas requesting a two-and-a-half-year delay in implementing desegregation. Although the district court granted the relief, the United States Court of Appeals for the Eighth Circuit reversed the district court's decision on August 18, 1958, and stayed its mandate pending appeal to the Supreme Court. By this time, the incident had evolved into a national issue: it had become a debate not only on racism and segregation but also on states' rights and the Tenth Amendment. The Court cited the Supremacy Clause of Article VI, which declares the Constitution to be the supreme law of the land, and Marbury v. Madison in holding that the states must abide by the Court's decision in Brown. Expectedly, many states' right advocates and state officials criticized the ruling as an attack on the Tenth Amendment. Moreover, they claimed the Court's decision on Cooper as being inconsistent with the constitutional vision of the Framers. Federal funding The federal system limits the ability of the federal government to use state governments as an instrument of the national government, as held in Printz v. United States. For this reason, Congress often seeks to exercise its powers by encouraging States to implement national programs consistent with national minimum standards; a system known as cooperative federalism. One example of the exercise of this device was to condition allocation of federal funding where certain state laws do not conform to federal guidelines. For example, federal educational funds may not be accepted without implementation of special education programs in compliance with IDEA. Similarly, the nationwide state 55 mph (89 km/h) speed limit, 0.08 legal blood alcohol limit, and the nationwide state 21-year drinking age were imposed through this method; the states would lose highway funding if they refused to pass such laws (though the national speed limit has since been repealed). In National Federation of Independent Business v. Sebelius (2012), the Court ruled that the Patient Protection and Affordable Care Act (commonly referred to as the ACA or Obamacare) unconstitutionally coerced the states