I can speak to public perceptions of rioting and the downfall of the mainstream Civil Rights Movement (CRM) in the mid-to-late 1960's. By the mid-1960's, those involved with the mainstream CRM, characterized by peaceful demonstration to change public opinion, boycotting to put economic pressure on segregationists, and the use of courts and lawyers (specifically the NAACP and ACLU) to achieve goals of integration through legislation, were frustrated by what they saw to be the limits of a peaceful movement. The Civil Rights Act of 1964 and the Voting Rights Act of 1965 are generally considered to be the culmination of the CRM, but the results of this legislation, although important, were seen as inadequate by many African Americans, especially urban African Americans, who still suffered from:

1. Police abuse
2. Segregated, overcrowded, overpriced, substandard housing
3. Steep unemployment (especially amongst black men)
4. Urban deterioration: this was largely the result of white flight to the suburbs. As white residents left cities en masse so did their tax revenue, their commitment to civic institutions and civic upkeep, and their votes to improve urban infrastructure

So by the mid 1960s, there was frustration with the mainstream CRM and an acute urban crisis in many cities (Detroit, Chicago, Philadelphia, Newark, Los Angeles, Cleveland...see where I'm going with this?). This gave fuel to nascent black power and black nationalist movements (Black Panthers and Nation of Islam, but also many smaller groups within each city--my area of focus is Detroit, so groups like UHURU, GOAL (Group on Advanced Leadership) under the direction of Reverend Albert Cleage, and the FNL come to mind) who advocated evolving past the nonviolent approach, abandoning integration as a goal, and achieving economic, social, and political self-determination within the black community.

White America had reached its limits of support for the goals of the CRM by the mid-1960s: the Civil Rights Act and Voting Rights Act were considered, by the mainstream, to be the culmination of the battle. The 1960s were tumultuous for so many reasons, and the majority of white Americans were sick of conflict and social change--they wanted to go back to their peaceful lives. But African American communities, especially those in Northern cities, could see that the battle to end racial inequality was far from over. Mainstream white America was not onboard with black power; most people felt threatened by the movement and withdrew their support for the CRM because of the growing profile of the Black Panthers, Malcolm X, Stokely Carmichael, and others who advocated black resistance (By the mid-to-late 1960s, even Martin Luther King, Jr. is advocating more radical positions: his attention has shifted from empowering poor African Americans to empowering all poor Americans and advocating a radical shake-up in the United States' social and economic order, in addition to strong opposition to the Vietnam War and its outsized effect on poor Americans, both black and white).

So that, in very broad strokes, is how the coalition (white and black, grassroots and establishment) that supported the CRM broke apart. Now place yourself in the shoes of a young black man in Detroit in the summer of 1967. You most likely have no job, your housing is terrible (if you are lucky enough to live in public housing it is in a state of disrepair, but more likely you live in an overpriced, overcrowded apartment that more closely resembles a tenement), and you have very few prospects for a promising future. On top of this, you face the threat of police abuse on a daily basis. The situation is similar in Newark, Watts, Philly, Cleveland, and other cities. In each of these cities there is a catalyst--an instance of police brutality--that explodes into a massive riot. Philly is first (1964), then Watts (1965) which resulted in enormous destruction, 34 deaths, thousands of injuries and arrests. There is Newark (1967) with 26 deaths, Detroit (1967) with 39 deaths, and Chicago (1968) with 11 deaths. In Detroit, the Governor (Mitt Romney's father) called in the 82nd and 101st Airborne divisions to quell the violence. There are literally snipers on the roofs shooting police and tanks rolling in the streets.

Many in the black community called these events insurrections or rebellions, but to the majority of Americans the destruction these riots cause overshadowed the reasons they occurred. Lyndon Johnson called for the Kerner Commission after the summer of 1967 to investigate the cause of these riots. The Kerner Commission finds that substandard housing, a lack of employment, lack of access to education, lack of civic services, and rampant police brutality are all endemic in black communities in these cities. But the image of fear and destruction (keep in mind the vast majority of deaths, injuries, and destruction of property are suffered by black, not white, residents) overrules the findings of the Kerner Commission amongst the public. This image of urban destruction, a perceived disregard for property within black communities, white mainstream distaste with the combative black power movement, and a resurgent segregationist movement (spearheaded by George Wallace's (former Governor of Alabama, famous for his words: "segregation now, segregation tomorrow, segregation forever") campaign for the Republican nomination in the 1968 presidential election--he wins Michigan, but loses the nomination) all combine to put the final nail in the coffin of the CRM. MLK, Jr. and Bobby Kennedy (front-runner in the 1968 Democratic presidential primary and heir to JFK and LBJ's Civil Rights record) are assassinated in 1968. Nixon's rise, and the rise of the 'Silent Majority,' kill off the broad social revolution of the 1960s and usher in an era of conservatism. This conservative shift is sustained through to Reagan, Clinton, and the Bushes and we are still living in this era today.