Here's a look at some of the most important cases decided by the U.S. Supreme Court since 1789.
1803 - Marbury v. Madison This decision established the system of checks and balances and the power of the Supreme Court within the federal government.
Situation: Federalist William Marbury and many others were appointed to positions by outgoing President John Adams. The appointments were not finalized before the new Secretary of State James Madison took office, and Madison chose not to honor them. Marbury and the others invoked an Act of Congress and sued to get their appointed positions.
The Court decided against Marbury 6-0.
Historical significance: Chief Justice John Marshall wrote, "An act of the legislature repugnant to the constitution is void." It was the first time the Supreme Court declared unconstitutional a law that had been passed by Congress.
1857 - Dred Scott v. Sandford This decision established that slaves were not citizens of the United States and were not protected under the U.S. Constitution.
Situation: Dred Scott and his wife Harriet sued for their freedom in Missouri, a slave state, after having lived with their owner, an Army surgeon, in the free Territory of Wisconsin.
The Court decided against Scott 7-2.
Historical significance: Slaves are not citizens and thereby cannot sue in federal court. The decision overturned the Missouri Compromise, where Congress had prohibited slavery in the territories. The Dred Scott decision was overturned later with the adoption of the 13th Amendment, abolishing slavery in 1865 and the 14th Amendment in 1868, granting citizenship to all born in the U.S.
1896 - Plessy v. Ferguson This decision established the rule of segregation, separate but equal.
Situation: While attempting to test the constitutionality of the Separate Car Law in Louisiana, Homer Plessy, a man of 1/8 African descent, sat in the train car for whites instead of the blacks-only train car and was arrested.
The Court decided against Plessy 7-1.
Historical significance: Justice Henry Billings Brown wrote, "The argument also assumes that social prejudice may be overcome by legislation and that equal rights cannot be secured except by an enforced commingling of the two races... if the civil and political rights of both races be equal, one cannot be inferior to the other civilly or politically. If one race be inferior to the other socially, the Constitution of the United States cannot put them upon the same plane." The Court gave merit to the "Jim Crow" system. Plessy was overturned by the Brown v. Board of Education decision.
1954 - Brown v. Board of Education
This decision overturned Plessy v. Ferguson and granted equal protection under the law.
Situation: Segregation of the public school systems in the United States was addressed when cases in Kansas, South Carolina, Delaware, and Virginia were all decided together under Brown v. Broad of Education. Third-grader Linda Brown was denied admission to the white school a few blocks from her home and was forced to attend the blacks-only school a mile away.
The Court decided in favor of Brown unanimously.
Historical significance: Racial segregation violates the Equal Protection Clause of the 14th Amendment.
1963 - Gideon v. Wainwright
This decision guarantees the right to counsel.
Situation: Clarence Earl Gideon was forced to defend himself when he requested a lawyer from a Florida court and was refused. He was convicted and sentenced to five years for breaking and entering.
The Court decided in favor of Gideon unanimously.
Historical significance: Ensures the Sixth Amendment's guarantee to counsel is applicable to the states through the 14th Amendment's due process clause.
1964 - New York Times v. Sullivan This decision upheld the First Amendment rights of freedom of speech and freedom of the press.
Situation: The New York Times and four African-American ministers were sued for libel by Montgomery, Alabama, police commissioner L.B. Sullivan. Sullivan claimed a full-page ad in the Times discussing the arrest of Dr. Martin Luther King, Jr., and his efforts toward voter registration and integration in Montgomery were defamatory against Sullivan. Alabama's libel law does not require Sullivan to prove harm since the ad did contain factual errors. He was awarded $500,000.