Prohibition was enacted following the passage of the Eighteenth Amendment. For many Americans it represented an unnecessary intrusion of rural, Protestant ideals on a key aspect of urban, working class life. The lax enforcement of the law, coupled with a significant demand for alcohol created, amongst other things, the rise of the American Mafia and widespread corruption in Politics and Civil Society. It was repealed thirteen years later, in 1933, with the passage of the Twenty-First Amendment. 

That quote is an excerpt from the Supreme Court’s ruling in the Brown v. Board of Education (1954) case. The case established that “separate but equal” was unconstitutional in practice, because it was inherently unequal. The case reversed a previous decision made by the Supreme Court, in 1896, in the Plessy v. Ferguson case, which had mandated that “separate but equal” was constitutional. It was a landmark case in the growing civil rights movement of the era.

Young women of the 1920s who dressed and behaved as such were collectively known as Flappers.

Migrants from Oklahoma and nearby states, like Arkansas, were lumped together and called "Okies."

The Roe v. Wade case made abortion legal in the United States. It dictated that a woman had the right to termination provided she was in the first trimester of her pregnancy. That has since been extended to roughly seven months, or whenever the baby could potentially live outside of the woman’s body. The case remains important in the United States today. Throughout the last few decades it has been a major social issue for several different factions and interest groups. 

Throughout the 1920s, controversies raged across the nation regarding whether Charles Darwin's theory of evolution should be taught in public schools. In 1925, the State of Tennessee passed the Butler Act, which specifically prohibited teaching evolution and allowed only creationism to be discussed in classrooms. In the tiny town of Dayton, a schoolteacher named John Scopes was convinced to challenge the law. After the American Civil Liberties Union and the famed lawyer Clarence Darrow came to Scopes' defence, William Jennings Bryan and various fundamentalist Christian groups defended the law. The subsequent trial, known popularly as the "Scopes Monkey Trial," became a celebrated national news story.

Before becoming the first African-American Supreme Court Justice, Thurgood Marshall had already made a name for himself in United States’ law and society. He argued convincingly for an end to segregation in Brown v. Board of Education, and many historians credit him with helping sway the Court in favor of ending segregation. He was appointed to the Supreme Court in 1967, having been nominated by President Lyndon B. Johnson. Marshall was a firm advocator for civil rights, constitutional amendment, and the reform of criminal procedure. He retired in 1991 and was replaced by Clarence Thomas, who became the second African-American Supreme Court Justice. 

Gideon v. Wainwright took place in 1963. It is considered an extremely important case in the earlier stage of the Civil Rights movement. In the case the Supreme Court ruled, unanimously, that state courts were required to provide a defense attorney to any defendant who did not have the means to pay for one. According to the Supreme Court, the existing Fourteenth and Sixth Amendments dictated that such a law was both Constitutional and necessary for upholding the rights guaranteed to all American citizens. 

The National Organization for Women was formed in 1966. It was not the first such institution to campaign for the advancement of women’s rights and equal status, but it has gained prominence in the years since, due to its effective campaigning. The Organization was formed in part by Betty Friedan, the author of The Feminine Mystique, and she went on to become its first acting President. 

The original Ku Klux Klan, which existed in the Reconstruction era in the South, was a secret-society terrorist organization seeking to frighten newly freed slaves and did not last past the 1870s. The Klan was reformed in 1914 at Stone Mountain, Georgia, with a more political and populist appeal, adding Jews, Catholics, immigrants, anti-prohibitionists, communists, and atheists to its list of enemies. The Second Klan saw widespread popularity in not just the South, but the West and Midwest as well. Well-known Klansmen held political office in many states, and the  conservative Evangelical spin on nativism gained much popular currency throughout the 1920s. After a series of scandals by Klan politicians, and a resumption of terror activity by certain Klan groups, the popularity of the Klan diminished.