The Great Migration generally refers to the period of time, in the first half of the twentieth century, when African-Americans migrated from the South to the North en masse. They were searching for greater social equality and job opportunities. By the end of the twentieth century, African-Americans were a distinctly urbanized community, with close to 90% of the population living in cities. 

Charles Schenck was the Secretary of the Socialist Part of America during World War One. He argued passionately that the young men being drafted to fight in the “Imperialist, European war” owed it to themselves and to the principles of the United States to resist the draft and the involuntary servitude it required. Schenck was indicted under the Espionage Act of 1917 and took his case to the Supreme Court. Schenck believed that his First Amendment rights to freedom of speech and press were being infringed upon by the Espionage Act; however, the Supreme Court ruled against him. The Court's majority verdict maintained that during times of war an individual did not have the right to speak out against military service or the draft. 

Margaret Sanger was a prominent feminist who pushed adamantly for the use of birth control and contraception in the first decades of the twentieth century. At the time it was generally held that women did not have the right to intercourse with the assurance that they might not get pregnant. Sanger worked as a nurse for several years and observed the trauma and hardship that unwanted pregnancies brought upon single and poor women, especially in inner cities. She distributed diaphrams freely to women and was tried and convicted for the practice. Her case attracted wide publicity and helped push forward a movement to change the law in 1918. Sanger founded the first American family planning and birth control clinic in Brooklyn, in 1916, and established the American Birth Control League in 1921.

Rosie the Riveter was an important cultural icon during World War Two. It was the term used to describe the American women who were replacing male workers in factories across the United States. The work of these women was vital to the war effort—they produced munitions and supplies. The effect of women entering the workplace in large numbers has been very significant for the growth of sexual equality in the United States and across the Western world.

In response to a rise in racist driven violence against African-Americans in the South and new factory employment opportunities in the North, large numbers of African-Americans left rural areas in the South for the urban areas of the North. This mass movement of people was one of the largest in American history. The "Great Migration" also drastically changed demographic patterns throughout the country from 1910-1960.

The Roe v. Wade case was argued by both sides with Fourteenth Amendment arguments regarding the rights of persons. Jane Roe (a psuedonym) had wanted an abortion, which was illegal in Texas at the time, and sued the state when she was unable to have one. In a surprising 7–2 decision, the Supreme Court found a implicit right to privacy in both the Ninth and Fourteenth Amendment's guarantee of a person's right. The decision made abortion in the first six months of pregnancy a guaranteed right that needed to be analyzed under strict scrutiny.

The Immigration Acts of 1924 included several provisions to restrict the immigration of people from certain parts of the world. Those from East Asia, the Middle East, and the Indian subcontinent were forbidden entirely from moving to the United States. People from Eastern and Southern Europe found their ability to settle in the United States heavily curtailed by the National Origins Act. The Act was passed largely to restrict the arrival of Jews from countries where they faced persecution, such as Poland and Russia. The National Origins Act overturned the earlier Immigration Restriction Act of 1921, which had set the cap at three percent. The Act remained in effect until 1965, when it was overturned by the Immigration and Nationality Act.

The Civil Rights Movement, led most notably by Martin Luther King, Jr., was a nonviolent movement that sought to end the Jim Crow style discrimination against African Americans throughout the country, mostly in the South. The movement was largely organized by ministers and found much support from the organization of black churches. Additionally, leaders encouraged civil rights lawyers, like Thurgood Marshall, to advance court cases that would end discriminatory laws and practices, such as segregation in schools, public transportation, and housing. Mass demonstrations, such as the March on Washington in 1963 and the Freedom March from Selma to Montgomery in Alabama, brought widespread attention to the cause.

The Keating-Owen Act was a series of reforms aimed at ending the use and abuse of child labor in American industrial practices. The act was passed by Congress in 1916 but rendered unconstitutional by the Supreme Court only two years later. The specific nature of the bill stated that goods produced in a factory or mine worked by children under fourteen years of age could not be sold in interstate trade. The Supreme Court overturned it on the grounds that it exceeded the federal government’s power to regulate interstate commerce; however, it represented an important beginning to the end of child labor abuses in America.

The Red Scare and the age of McCarthyism were both time periods during the United States in which American sentiment was extremely strong and powerful, and those who expressed anti-American views, or pro-Communism views, were chastised and criticized for being unpatriotic.