Pluralism is the name given to a political theory—widely accepted in most modern democracies—that states that a democratic society benefits when there are many competing and varied individual and group opinions working together, or in competition with each other, to direct public policy.

The President and both Houses of Congress are elected by a vote of the people. Supreme Court Justices, however, are appointed by Presidents. The appointment has to be approved by the Senate.

Perhaps despite the wishes of many Presidents who have battled oppositional Congresses, the President is not provided with any power to alter the membership of Congress by appointing or firing members, nor can the President call for new elections. The President also must abide by the laws that the Congress passes. Article I Section 7 of the US Constitution does, however, grant the President the power to refuse to sign a bill from Congress or to outright veto it. This power allows the President some power to oppose legislation they find unacceptable, but Congress can override a veto. Overriding a veto requires much higher support (2/3 "super-majority") within Congress for the bill. 

In the American government power is separated into three branches. The Legislative Branch makes laws, the Executive Branch carries out and enforces laws, and the Judicial Branch interprets whether or not laws violate the Constitution.

The McCarran Act was signed into law in 1950; it was part of the Red Scare period of American history. The McCarran Act required all Communist organizations and members to register their affiliation with the United States government.

The Equal Protection Clause appears in the Fourteenth Amendment to the United States Constitution. It prohibits the states from denying equal protection under the law to anybody on the basis of race, gender, or other forms of discrimination. It also essentially ensures that the Bill of Rights are extended to cover actions taken by state governments as well as the national government.

The Alien and Sedition Acts were passed in 1798, during the Presidency of John Adams. The Alien and Sedition Acts were released during the so-called Quasi War with France, and sought to (in theory) increase national security by making it illegal to speak out against the government, and by making it harder for immigrants to come to the new nation. The Acts were denounced by Thomas Jefferson and the Democratic-Republicans as an attempt to solidify the power of the Federalist Party, which helped propel the Democratic-Republicans into the Presidency in 1800.

The main reason the South seceded from the Union is that it felt that the states should have greater control over the direction of their laws and should be less subservient to the federal government. The majority of Southerners in this time period identified more with their state than with the nation. So, the Civil War can be seen as a conflict over the interpretation of American Federalism. The South felt that the system of Federalism should divide powers more equally between the state and national governments, and the Union felt otherwise. This disagreement was effectively resolved (legally speaking) with the passage of the Fourteenth Amendment, which outlined the requirements for states to abide by national laws.

For the first one hundred and fifty years of American political history, the country essentially operated under Dual Federalism, also called "Layer-cake Federalism." This involves a clear delineation of powers reserved for national governments, state governments, and local governments. During the Great Depression, the power of the Federal government grew dramatically, and the United States' federalism system began to appear more like Cooperative Federalism, also called "Marble-cake Federalism." In Marble-cake Federalism, national, state, and local governments work together cooperatively to tackle problems and pass laws.

Nullification declares that the states have the right to declare any federal law unconstitutional or illegal and choose to ignore it within the state itself. This position was championed particularly by Thomas Jefferson as is the central point of the Kentucky and Virginia Resolutions. Because nullification involves the repudiation of the ultimate authority of the national government, it can be understood as a rejection of the Supremacy Clause, which states that the Constitution and the national government make up “the supreme law of the land.”