Federalism can be defined as “a system of government in which sovereignty is divided between a central authority and constituent political units, such as states or provinces.” What this means is that power is within a country is shared between the state and local governments, forcing them to work together in order to make decisions that impact the nation on a national level and at a more local level. Over time, federalism has gone through many different developments in terms of changes to the Constitution and political scientists who study constitutional jurisprudence have chosen to break down these developments in four different chronological eras. Beginning in 1789 with the ratification of the Constitution, the concept of federalism as been interpreted by the Supreme Court either narrowly or in more of a broad manner, with each of the four eras correlating to a specific type of interpretation by the Court. After the Constitution was written and signed into law in 1787, questions of federalism began to rise up from the state governments, thus beginning what is referred to as the Federalist Period of federalism. One of the first cases that put the question of federalism in everyone’s mind was Gibbons v. Ogden in 1824. The case related to the commerce clause and even more specifically the power to regulate navigation. The constitutional question and hand was “Does Congress have the power to regulate interstate monopolies?” The court held to a broad interpretation, saying the federal government does in fact have the power to regulate interstate monopolies. In terms of taxing and spending during the Federalist Period, I will cite the case Springer v. US (1881). In 1864 Congress passed the Federal Revenue Act, which imposed a federal income tax and that leads up to 1881 when Springer challenges the court on the grounds that the Revenue Act is unconstitutional in that it imposes a “direct tax”. The court again holds a broad interpretation, siding with the US in saying that direct taxes only refer to “real property” and “slaves”. In regards to the 14th amendment, it was also interpreted broadly in the case Barron v. Baltimore, where the court said that the Bill of Rights was in fact applicable to state governments. This case set precedent for many other future cases dealing with similar issues making it a landmark decision in Supreme Court history. To finish off the Federalist Period, the 10th and 11th amendments were surprisingly interpreted narrowly in the case McCulloch v. Maryland when the court does hold that Congress does have the power to establish a national bank. After the Federalist period people began to get sick of the feds interfering with state affairs, and this shows by the narrow interpretations that occurred during the second era of federalism. The second era of federalism was named after the type of federalism that mostly takes place during the 70-year period. The Dual Federalism era was the first time in a while where state and local governments started to get some power delegated to them through decisions made by the Supreme Court. When dealing the with commerce clause I’ll name the decision made in the case US v. EC Knight where the constitutional question is as follows: “Is the Sherman Anti-Trust Act a proper use of the necessary and proper claus