The following are brief synopses of important Supreme Court decisions in American history:

1803
Marbury vs. Madison

On his way out of office, President John Adams pushed several appointments to fill as many government posts as possible with Federalists. When incoming President Thomas Jefferson refused to honor the appointees, one appointee, William Marbury, sued James Madison, the new Secretary of State, to deliver the appointment. In Marbury vs. Madison, Chief Justice John Marshall established the power of judicial review: The ability of the court not only to interpret the constitutionality of a law or statute, but also to carry out the process and enforce its decision - something not explicitly stated in the Constitution. Ultimately, the case established the court's power to declare acts of Congress unconstitutional. 

1819
McCulloch vs. Maryland
 
McCulloch vs. Maryland involved a federal agency set up by Congress which the state of Maryland wished to tax. The case resulted in two major conclusions. First that the "necessary and proper clause" in Article I, Section 8, of the Constitution permitted Congress to establish a United States Bank, despite the fact that this power was not expressly stated in the Constitution. This definition broadened congressional power. Second, the Court also established the supremacy of the federal government over the states. 

1824
Gibbons vs. Ogden

Gibbons vs. Ogden dealt with interstate commerce in the form of steamboat operation between states. The issue was whether a New York statute that prohibited vessels licensed by the federal government from navigating state waters was unconstitutional and, therefore, void. The Court used this case to lay the framework for extensive federal regulation of interstate commerce. 

1857
Dred Scott vs. Sanford

This notorious slavery case dealt with a slave (Scott) who was taken by his owner (Sanford) into northern territory. At issue was whether Scott was a citizen of the U.S. and legally entitled to use the courts to sue his owner for his freedom. The Supreme Court in this case ruled that slaves were property, not citizens and, therefore, not entitled to use the courts. 

1896
Plessy vs. Ferguson

Homer Plessy, a mixed-race citizen, purchased a first-class ticket on the East Louisiana Railway. He was asked to sit with the non-whites, did not move and was ejected with force from the train. He was sent to jail for violating the Louisiana Act of 1890, which required railway companies to provide "separate but equal" accommodations for both whites and blacks. The Supreme Court ruled that the Louisiana Act did not violate the Constitution and that "separate by equal" was a reasonable approach considering social prejudices of the time. 

1944
Korematsu vs. United States

During World War II, Fred Korematsu, an American citizen of Japanese descent, was convicted in federal court for refusing to go into the American prison camps ostensibly designed to protect the West Coast from acts of espionage and sabotage. The Court upheld the ruling 6-3, agreeing that an entire race could be labeled a "suspect classification." The government was given the power to deny the Japanese their constitutional rights because of military considerations. 

1954
Brown vs. Board of Education of Topeka

In this landmark case, four black children asked to be admitted to the all-white public schools in their community. The court struck down Plessy vs. Ferguson's "separate but equal" ruling, despite the fact that the all-black schools were equal to the all-white schools with respect to buildings, curriculum, qualifications and salaries of teachers, and other "tangible" factors. The Court looked not to the "tangible," but to the effect of segregation itself, calling separate educational facilities: "inherently unequal." The opinion sparked a massive shift in race relations across the country. 

1962
Engel vs. Vitale

In Engel vs. Vitale, the Board of Education of Union Free School District No. 9 in Hyde Park, New York was instructing the students of their district to say a specified nondenominational prayer each day. Some parents responded by calling the prayer a violation of the First Amendment's separation of church and state. The court agreed with the parents, saying that: "it is no part of the business of government to compose official prayer." 

1964
New York Times Co. vs. Sullivan

New York Times vs. Sullivan concerns a full-page ad in the New York Times which alleged that the arrest of the Rev. Martin Luther King Jr. for perjury in Alabama was part of a campaign to destroy King's civil rights work. Sullivan, the Montgomery city commissioner, filed a libel action against the newspaper and four black ministers who were listed as endorsers of the ad. The court said that public officials may not win damages for defamatory statements about their official conduct unless they can prove "malice" (with knowledge that they are false or in reckless disregard of the truth). 

1966
Miranda v. Arizona

Ernesto Miranda was convicted of rape and kidnapping due to incriminating statements he made to the police while they interrogated him. At no time during the questioning did the police inform Miranda he had the right to a lawyer, or that he did not have to talk to them. By an unpopular, narrow 5-4 decision, the Court ruled that his constitutional rights under the Fifth, Sixth and Fourteenth Amendments had been violated. The ruling required police to inform suspects in custody of their right to remain silent, that anything they say may be used against them and that they have a right to representation by a lawyer before interrogation. 

1973
Roe vs. Wade

In Roe vs. Wade, a Texas woman challenged a Texas abortion law on the grounds that the law violated her right of personal liberty given in the Fourteenth Amendment and her right to privacy protected by the Bill of Rights. The Supreme Court ruled that states could regulate abortions only in certain circumstances. They split the pregnancy into three time periods: in the first trimester, states were forbidden to interfere with a woman's decision to have an abortion; in the second trimester, states could regulated abortions, but only if such regulation was reasonably related to the mother's health; and in the third trimester, states could ban abortions altogether in order to protect the unborn child. 

1974
United States vs. Nixon

During the Watergate scandal, the special prosecutor subpoenaed certain tapes and documents of specific meetings held in the White House. President Nixon's lawyer sought to deny the subpoena. The court ruled that neither the deference afforded the president nor the doctrine of "separation of powers" gives a president an absolute privilege of immunity By an 8-0 vote, the court decided that Nixon must hand over specific tapes and documents to the special prosecutor. 

1978
University of California Regents vs. Bakke

In a deeply divided case, Allan Bakke, a white male, applied to the University of California at Davis Medical School. He did not meet the standard entrance requirements and was turned away. He argued a case of reverse discrimination because only black, Hispanic and Asian students could compete for a set number of spots reserved for minorities who did not meet the standard entrance requirements. The court ended up supporting Bakke's claim, while approving the use of race as one of the criteria in selecting applicants.