There are three major types of government in the place in the world today. The most prevalent is the unitary system. In a unitary system, power is held at the national level, with very little power being held in political subdivisions, such as provinces, counties, parishes, or towns. The least common is the confederation. Confederations are unions of equal states, with some power being held at the national level. Generally, it has been found that conflicting interests lead to the breakdown of confederations.The third major system is the federal system. In a federal system, the national government holds significant power, but the smaller political subdivisions also hold significant power. The United States, Canada, Australia, and Brazil are examples of federal systems. Federal systems are chosen for a number of reasons. The size of the nation might be one concern; the diversity of the political subdivisions might be another. The United States combines a bit of both: the size of the continental United States made a unitary system unwieldy, and the diverse interests of the states made confederation impossible. Nations like Switzerland have a population split by language, and despite its small size, found federalism to be a better choice than the others. China, being an extremely large and extremely diverse nation, finds the unitary system more suited to its political ideology. Federalism in the United States has evolved quite a bit since it was first implemented in 1787. In that time, two major kinds of federalism have dominated political theory. The first, dual federalism, holds that the federal government and the state governments are co-equals, each sovereign. In this theory, parts of the Constitution are interpreted very narrowly, such as the 10th Amendment, the Supremacy Clause, the Necessary and Proper Clause, and the Commerce Clause. In this narrow interpretation, the federal government has jurisdiction only if the Constitutio...
