What are the most influential rulings of the Supreme Court of the United States? With so many cases dubbed "landmark" decisions, it is hard tell what cases have the most impact. However, it is my view that a truly "landmark" case is one that is A) typically an older case with a ruling that sets a precedent for future Supreme Court decisions; and B) one that has lasting political and/or economic consequences for the citizens and institutions of the United States. With this in mind, here are what are, in my opinion, the five top "landmark" case rulings from the United States Supreme Court:

1. Marbury v. Madison (1803)

This case ruling is by far the most important that the Supreme Court has ever handed down. No other case could have been decided had not the Court established in Marbury the right to interpret the meaning of the Constitution, a power known today as judicial review. When President Thomas Jefferson refused a man named William Marbury his undelivered commission meant to be issued by the previous president's administration, Marbury appealed to directly to the Supreme Court. Although the Constitution didn't grant the Supreme Court the original jurisdiction it needed to hear and decide on the case, Marbury pointed to Section 13 of a law known as the Judiciary Act of 1789, which expanded the Court's power to cases like Marbury's. In response, the Supreme Court wrote in its official opinion that no law that contradicts the Constitution is a valid law, and that because Section 13 expanded the Court's power beyond its constitutional limits, that section was unconstitutional. Thus, Marbury lost the case, but the Supreme Court established the ability to interpret the Constitution and to apply it to federal law, setting a precedent that allowed the Court to interpret the Constitution in all cases after.

2. Chicago, Burlington & Quincy Railroad Co. v. City of Chicago (1897)

A case oft overlooked by history, the ruling nonetheless has had vast implications on future cases involving the federal Bill of Rights of the Constitution and how (if at all) it applies to state and city governments. Up until this point, the Supreme Court had always ruled that the Bill of Rights applied only to the federal government; state legislatures and city councils were free to govern their populations as they saw fit, unimpeded by virtually any constitutional limitations except their own. When the City of Chicago seized the private property of a railroad company, and in a city court case gave the company one dollar for the property, the railroad company appealed to the Supreme Court for help.

The Supreme Court wrote that the Fifth Amendment of the United States Constitution, which required the federal government to give "just compensation" for any seized property, applied also to state and local cases per the Fourteenth Amendment's Due Process Clause, which reads that no "State [will] deprive any person of life, liberty, or property, without due process of law..." Thus, the City Council was under obligation to give just compensation to the railroad company. However, the Court ruled that the Council had indeed done that, so in truth the case only established the Court precedent of using the Fourteenth Amendment to apply the Bill of Rights to state and local governments, albeit selectively.

3. Brown v. Board of Education (1954)

The ruling of this case was a monumental victory for the American civil rights movement. At a time when state and local governments had for years enforced rigid laws segregating whites and blacks under a principle of "separate but equal" accommodations for both races, plaintiff Oliver Brown and the NAACP appealed to the Supreme Court over segregation policies in Kansas schools in the City of Topeka, arguing that the "separate but equal" doctrine did not actually give blacks services on par with the services given whites.

The Supreme Court ruled that the Equal Protection Clause of the Fourteenth Amendment, which read that a state could not "deny to any person within its jurisdiction the equal protection of the laws," calling for an end to segregation in public schools. This ruling was a step toward broader civil rights for African Americans, culminating in the Civil Rights Act of 1964, which outlawed racial discrimination in public institutions and facilities.

4. Brandenburg v. Ohio (1969)

A case that outlined the Supreme Court's views on the Free Speech Clause of the First Amendment, the Brandenburg ruling overruled virtually any restrictions on speech that did not incite "imminent lawless action." When Ohioan Ku Klux Klan leader Clarence Brandenburg spoke at a 1964 KKK rally, he made a speech which he allowed to be recorded, threatening revenge on blacks and Jews, as well as plans to organize a march to Washington D.C. When the speech was made public, Brandenburg was arrested under a criminal syndicalism statute that restricted his speech. He appealed to a lower state court, claiming that the arrest was in conflict with his First and Fourteenth Amendments of the United States Constitution. He moved through the entire Ohio state court system, with each court deciding against him.

Brandenburg appealed to the United States Supreme Court, which ruled that the Fourteenth Amendment applied the First Amendment to the state and local governments, and that Ohio's criminal syndicalism statute was unconstitutional. Brandenburg, the Court wrote, had a right to say what he pleased, and that only speech which provoked "imminent lawless action" could be regulated in any way. The Court wrote that he had not incited any "imminent lawless action" at the KKK rally, and his criminal convictions were overturned. Since 1969, the Court has said that restrictions on free speech can include "time, place, and manner" and prior restraint (a law against certain speech before it is spoken). With few exceptions, speech, however ugly, has been protected by the Supreme Court.

5. Roe v. Wade (1973)

Although this case is fairly recent, it's impact on the abortion debate and on abortion law cannot be understated. The Court, in Roe, established abortion as a woman's constitutional right. The plaintiff, anonymously dubbed "Roe," could not obtain an abortion in Texas due to restrictions in the state, appealed to the Supreme Court, which ruled that her Fourteenth Amendment Due Process Clause and the right to privacy under the Ninth Amendment had been violated, striking down the Texas law and legalizing abortion. While the Court has since modified its 1973 opinion allowing for some governmental regulations on abortion, Roe paved the way for organizations like Planned Parenthood to rise to prominence, making abortion on demand easier to obtain.

Since Roe, more than 60 million infants have been killed by abortions performed in the United States, a number greater than the all U.S. war casualties combined (1,320,000). The debate surrounding abortion since 1973 has become more vocal over time, with the pro-life movement arguing that it violates the infant's right to life and the pro-abortion movement arguing that it is a woman's right to choose. In recent years, however, states such as Georgia, Alabama, and South Carolina have passed pro-life legislation, with Alabama passing a law banning nearly all abortions in the state, excepting at the risk to the mother's health. Whether Roe will be reversed and abortion made illegal in the United States has yet to be determined, but Roe's impact on abortion law and human rights debates has been astronomical, and will continue to be a subject of great controversy for years to come.

So these are my top five Supreme Court cases. Do you agree? Do you have your own top five? Let me know in the comments!