Question: Paul A. Freund is known for his writings on what supreme law of the United States of America?

<P0-S0> The Supremacy Clause of the United States Constitution (Article VI, Clause 2) establishes that the Constitution, federal laws made pursuant to it, and treaties made under its authority, constitute the supreme law of the land. <P0-S1>  It provides that state courts are bound by the supreme law; in case of conflict between federal and state law, the federal law must be applied. <P0-S2>  Even state constitutions are subordinate to federal law. <P0-S3>  In essence, it is a conflict-of-laws rule specifying that certain national acts take priority over any state acts that conflict with national law. <P0-S4>  In this respect, the Supremacy Clause follows the lead of Article XIII of the Articles of Confederation, which provided that "Every State shall abide by the determination of the United States in Congress Assembled, on all questions which by this confederation are submitted to them." <P0-S5>  A constitutional provision announcing the supremacy of federal law, the Supremacy Clause assumes the underlying priority of federal authority, at least when that authority is expressed in the Constitution itself. <P0-S6>  No matter what the federal government or the states might wish to do, they have to stay within the boundaries of the Constitution. <P0-S7>  This makes the Supremacy Clause the cornerstone of the whole American political structure. <SEP> <P1-S0> Ernst Freund (January 30, 1864 in New York City – October 20, 1932 in Chicago, Illinois) was a noted American legal scholar. <P1-S1>  He received a Dr. Jur. <P1-S2>  from the University of Heidelberg (1884); a Ph.D. in political science from Columbia University (1897) He was professor of political science at the University of Chicago (1894–1902) and professor of law at Chicago (1903–32). <P1-S3>  He was John P. Wilson Professor of Law (1929–1932). <P1-S4>  Freund was principally responsible for the development of administrative law in the United States during the early twentieth century. <P1-S5>  He was one of the organizers of the Immigrants' Protective League (1908). <P1-S6>  The University of Chicago Law School has established the Ernst Freund Distinguished Service Professorship of Law and Ethics in his honor, a seat currently held by philosopher Martha Nussbaum. <SEP> <P2-S0> Paul A. Freund (February 16, 1908—February 5, 1992) was an American jurist and law professor. <P2-S1>  He taught most of his life at Harvard Law School and is known for his writings on the United States Constitution and the Supreme Court of the United States. <SEP> <P3-S0> The United States Constitution is the supreme law of the United States of America. <P3-S1>  The Constitution, originally comprising seven articles, delineates the national frame of government. <P3-S2>  Its first three articles entrench the doctrine of the separation of powers, whereby the federal government is divided into three branches: the legislative, consisting of the bicameral Congress; the executive, consisting of the President; and the judicial, consisting of the Supreme Court and other federal courts. <P3-S3>  Articles Four, Five and Six entrench concepts of federalism, describing the rights and responsibilities of state governments and of the states in relationship to the federal government. <P3-S4>  Article Seven establishes the procedure subsequently used by the thirteen States to ratify it.