IN THE 1960s, FRACTURES along lines of race, class, gender, religion, sexual orientation, and political ideology greatly impacted institutions and public discourse in ways that continue to shape American policy and culture today. In significant ways, societal divisions were exacerbated following the Immigration Act of 1965, which ended national origin quotas and spurred an influx of immigrants from new parts of the world, especially Asia, South America, and Africa. Combined with the increasingly globalized economy that resulted from free-trade policies and technological advancements, America grew more diverse.

Popular music styles have evolved considerably over the years since America's founding, however the rate of change increased dramatically starting in the 1950s, in part fueled by the diversification of the nation. Stylistic plurality also extended from the rise in the 1950s of the business practice of "planned obsolescence," in which products are created to break down or go out of style relatively quickly so that consumers will regularly purchase them.

Music in these years also became more than a form of entertainment and the result is that music was heard everywhere. Studies showed that music could encourage more spending in stores, it could soothe nerves on airplanes and in elevators, it could reduce stress in the dentist's chair, and it could reduce the need for anesthesia during surgical operations and promote healing. The list of the benefits from listening to music continues to grow daily.

Technology has greatly expanded music's prevalence. The development of lightweight headphones and digital technologies, eventually resulting in compact discs and MP3 players, increased both the portability and personal enjoyment of music. It became possible to listen privately to music anywhere and at any time.

The introduction of music videos on the all-music television channel MTV (introduced in 1981) had a significant impact on the composition, marketing, and dissemination of songs. Music was no stranger to television, of course. Dick Clark's shows American Bandstand and Where the Action Is along with others, such as Ninth Street West, had featured dancing teenagers with the occasional live performance by a band. However, MTV raised the medium to an artistic, creative expression where a no-holds-barred attitude allowed musicians to interpret music for their audience in more complex ways. Many performing groups who were unable to meet the demands of radio formats were given significant exposure on MTV. The result was that music was no longer strictly an aural experience; it became a visual experience as well.

Videos did not displace live concerts, however, which became extravagant money-makers. From the late 1960s, when bands were hired to play college campuses and large private parties, rock concerts expanded to fantastic crowds that flocked to football stadiums and arenas. Because of the significant profit potential, many musicians staged benefits for various worthy causes. Starting in 1985, charity rock concerts were staged as musicians' "aid." Live Aid was held in support of organizations fighting worldwide famine (also known as Band Aid), and Farm Aid benefitted rural farmers in Middle America.

Computers enabled songwriters to compose music with sounds generated digitally, expanding the creative palette extensively. Songwriters were capable of recording any sound in any way that they wished. Musical styles developed into complex, multifaceted outlets for a variety of expressions. The cookie cutter approach that was applied to the songs of Tin Pan Alley became more personal as different types of songwriting were utilized for different expressions.

As innovations appeared, songwriters kept pace in an ever-increasing frenzy of change. The results were a continuous process of "style fragmentation." As popular music styles evolved and songwriters put their own stamp on them, sub-styles emerged. As these sub-styles split further, the multiplicity of possibilities grew, especially when combined with the increasing incidences of "crossovers," involving a fusion of different styles that appeal to more than one audience.

Rock and roll gave way to rock, which in turn split into hard rock, soft rock, prog rock, punk rock, southern rock, alternative rock, grunge, and even more subgenres. Country music was divided between the smooth and lavishly produced "Nashville sound," the edgier "Bakersfield Sound," and politically left-leaning "progressive country." The mambo craze of the 1950s led to salsa in the 1960s and 1970s and Latin pop in the 1980s and 1990s. Motown and soul inspired funk, which evolved into both disco and hip-hop. And so on.

It is difficult, if not impossible, to generalize about specific styles because there were almost as many as there were songwriters. However, it is possible to trace certain musical and social trends.

American involvement in Vietnam dated to the Eisenhower administration and was escalated by both Presidents Kennedy and Johnson, under whom it broadened into a full-blown war against the spread of communism in 1964. By the late 1960s, many Americans had grown disillusioned with Johnson's handling of the Vietnam War. It was the first war to be filmed, and news coverage painted a grim picture. The Tet Offensive, a month-long operation in which the communist Vietcong attacked over 100 cities and towns and a dozen US military bases, exposed that Johnson's past assertions that the US was succeeding in Vietnam were misleading. News of the My Lai Massacre, in which American soldiers murdered hundreds of Vietnamese citizens—many of them children, infants, and elderly—undercut America's moral authority.

By 1967, the anti-war movement had moved from the fringes of society into the mainstream. In April, civil-rights leader Martin Luther King, Jr. voiced his opposition to the war, and the following October nearly 100,000 protesters rallied at the Lincoln Memorial and marched to the Pentagon. Also that year, the organization Vietnam Veterans Against the War was founded, and its members began protesting by throwing their medals onto the White House lawn.

Music and musicians increasingly participated in the anti-war effort. In the summer of 1969, some 400,000 people gathered at the Woodstock Music and Arts Fair in Bethel, New York, for three days of what was advertised as "peace and music." The list of stars, including Joan Baez, Crosby, Stills, Nash and Young, Janis Joplin, the Grateful Dead, the Who, Santana, Creedence Clearwater Revival, Jefferson Airplane, and many others, demonstrates the extent to which the anti-war movement and counterculture had entered the mainstream. For many, Jimi Hendrix's famously distorted electric-guitar rendition of "The Star Spangled Banner" represented their view that America had distorted its ideals and perverted its institutions.

With the anti-war movement growing, in March 1968 Johnson announced his decision to not seek reelection. The Democrats nominated Hubert Humphrey, but Republican Richard Nixon's promises to end the draft, reinstate law and order throughout the country, and bring the war to a conclusion swept him into the Oval Office.

Despite Nixon's pledges, American involvement in the war—and demonstrations against it—raged for nearly five more years. University campuses had become hotbeds for the anti-war movement, fueled by moral outrage and dissatisfaction with changing draft policies. Initially exempt from conscription, in 1966 students found themselves suddenly eligible for the draft. At first, the affluent and privileged were largely able to avoid conscription, a fact maligned by the rock band Creedence Clearwater Revival in "Fortunate Son" (1969):

  Some folks are born made to wave the flag
Oh, they're red, white and blue
And when the band plays "Hail to the chief"
Oh, they point the cannon at you, Lord
It ain't me, it ain't me, I ain't no senator's son
It ain't me, it ain't me, I ain't no fortunate one, no.

Throughout the later decades of the twentieth century, Native Americans continued to struggle for recognition and fair treatment. As was common following the Second World War, musicians highlighted Native American veterans during powwows to project a patriotic and positive image of indigenous people. New music, such as "Vietnam Veterans Song," was written to honor new generations of veterans.

Other Native Americans were more combative. The Red Power Movement, which had first emerged in the 1950s, continued to raise awareness and protest the US government's breaking of treaties and lack of support for Native peoples. In 1968, Native Americans came together and created the American Indian Movement, which sought to protect Native Americans from police brutality. Severt Young Bear, a member of the Oglala Lakota Tribe, wrote "The AIM Song" as a kind of theme song for the organization.

AIM was involved in a number of highly publicized protests in the late 1960s and early 1970s. From November 1969 to June 1971, a group of students led the Occupation of Alcatraz Island in the San Francisco Bay in protest of the Federal Relocation Program that had offered incentives to encourage Native Americans to leave their reservations and move to urban centers. The program had been discontinued in 1963, and it had left many Native Americans stranded in poverty with few resources to lift them out of it. Other protests were directed at broken treaties, including the Mount Rushmore Occupation in 1971 and the Occupation of Wounded Knee in 1972 and 1973.

In the aftermath of the Second World War, world powers worked together to integrate their economies to promote cooperation and reduce the chances of another global war. The period witnessed the emergence of the European Union, the World Trade Organization, and free-trade agreements such as the North American Free Trade Agreement between the United States, Canada, and Mexico. Coupled with new developments in travel and telecommunications, the world became interconnected to an unprecedented extent.

In this context, many American musicians have integrated different instruments and musical characteristics from musics from across the globe. Paul Simon, for example, has integrated African instruments and performers as well as rhythmic and vocal styles into his music. Such music is not without controversy. While many fans celebrate it as emblematic of intercultural exchange and tolerance, others decry it as cultural appropriation.

Globalization is also linked to increased immigration in the late twentieth century. Immigrants have contributed in myriad ways to America's musical soundscape. Many expressed ethnic pride and encouraged interracial empathy and understanding. This was particularly evident in songs such as "Yo Soy Chicano" (1968; VAT Unit 8), a popular work that articulated the frustration of Mexican Americans who felt neglected by the Civil Rights Movement. Decades later, after significant increases in the Latin American population, Gloria Estefan's "Oye Mi Canto" (1989) continued the appeal for awareness and understanding of communities from all countries.

Many Latin Americans worked in poor labor conditions with few protections. The successful Delano Grape Strike and Boycott (1965–70), led by Cesar Chávez and including Filipino farmworkers, exemplifies workers' efforts of the period. The traditional corrido was the favored media for memorializing these important events. El Teatro Campesino, founded around this time to support the striking farmworkers, heralded the beginning of a thriving artistic community for Chicanos that included theater works by, for, and about Mexican immigrants in the United States.

The publication of Rachel Carson's Silent Spring in 1962 made the dangers posed by the mistreatment of the environment a household issue. Silent Spring focused on the use of chemicals and led to the banning of DDT in 1972; it also helped inspire the broader environmentalist movement.

In the 1960s and 1970s, Congress passed the first of several significant pieces of legislation aimed at protecting the environment, including the Clean Air Act (1963), Clean Water Act (1972), and Endangered Species Act (1973). To oversee the implementation and enforcement of these laws, in 1970 President Nixon created the Environmental Protection Agency. Also in 1970, Americans celebrated the first Earth Day, which was established to raise awareness about environmental issues.

Musicians also helped raise awareness about the environment. Joni Mitchell's "Big Yellow Taxi" (1970; VAT Unit 8) lamented ongoing urban development, and on his groundbreaking album What's Going On (1971), Marvin Gaye asked, "Where did all the blue skies go?" Many other songs appeared in the growing repertoire of songs about the environment, including the Kinks' "Apeman" (1970), Bob Dylan's "License to Kill" (1983), the Pretenders' "My City Was Gone" (1984), and Metallica's "Blackened" (1988).

Throughout the 1970s and 1980s, concerns grew over acid rain, deforestation, toxins in the air and ground, and the growing hole in the ozone layer of the atmosphere. In the 1980s, the issue of global warming, now more commonly referred to as "climate change," first became a highly controversial political issue. The issue pitted scientists against the fossil fuel industry.

The 1979 incident at the Three Mile Island Nuclear Power Plant in Pennsylvania and the meltdown of the nuclear power plant in Chernobyl in 1986 all but eradicated support for replacing fossil fuels with nuclear power.

After the Three Mile Island incident, many musicians came together to oppose nuclear power, forming Musicians United for Safe Energy (MUSE). Artists and bands including James Taylor, Carly Simon, Tom Petty, and many others, participated in concerts and released an album, titled No Nukes, in 1980.

In the 1990s, many musicians called for better treatment of the environment. Rocker Joe Walsh dedicated an entire album to the environment in Songs for a Dying Planet (1992). Michael Jackson supported conservationism in "Earth Song" (1995), asking,

  What about animals
We've turned kingdoms to dust
What about elephants
Have we lost their trust
What about crying whales
We're ravaging the seas
What about forest trails
Burnt despite our pleas.

The Six Nations Women Singers, one of the most well-known Native American groups, combine environmentalism with social criticism in "Mother Earth" (1995). They sing, "The Earth, our Mother, is crying tears, Earth is shedding tears for the bad thing our 'young brothers' [white people] have been doing to her."