The Harlem Renaissance peaked in the 1920s as a result of the freedoms for African Americans offered by the North. As many African Americans moved from the Jim Crow laws of the south, they pushed for tangible goals and a more positive image. The Cotton Club, the most most famous of nightclubs, was a home of many of these musicians, but still only offered whites admittance. The flappers followed this incredible influx of music and art, as did the rise of organized crime and the Black Sox Scandal of 1919.

Post-war and 1950s America is most commonly characterized as a time of massive population growth and economic prosperity. Americans returning from World War II were assisted back into society by the G.I. Bill, which provided for the higher education of veterans. Many American families that had been set back by the outbreak of war made up for lost time and the “baby boom” precipitated massive population growth over the next fifteen years. The “baby boom” in turn then encouraged the growth of consumerism which maintained economic prosperity even in the face of a rapidly advancing Social Security program. Political reforms were existent in the post-war years, as they are in all eras, but the major reforming movements would come into existence in the 1960s as the generation of “Baby Boomers” began to battle the established social and political norms. 

The term “Second Reconstruction” is used to refer to the Civil Rights Movement of the 1950s and 1960s. What is implicitly implied is that the first period of Reconstruction failed to achieve the proper emancipation and status of Blacks in America; therefore a “Second” Reconstruction was required in order to align society correctly. The rulings of the Warren Court were crucial to the Civil Rights Movement; however that answer is significantly less inclusive.

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.