Riots can occur without a specific reason or disagreement. In 1919 Boston became enflamed when people used a policemen's strike as an opportunity for extensive criminal activity, such as robbery, stoning striking policemen, and other kinds of assaults. The end of World War I and the summer immediately following it saw racially motivated riots in East St. Louis and Chicago, Illinois, and Washington, D.C., Major politically motivated riots also occurred, most notably those that protested the war in Vietnam. In the summer of 1968 civil rights and antiwar protesters joined in a march outside the Democratic National Convention in Chicago.
Riots in the late twentieth century seemed especially senseless, partially because television coverage allowed many to view the chaos as it was happening. When Los Angeles went up in flames in April 1992, the riot was ostensibly caused by the acquittal of the white police officers accused of beating an African American, Rodney King, a year earlier. A new element of protest was introduced in the Seattle riots when the Internet was used to call thousands to the city and spread the anarchistic gospel of the rioters.The elements that comprise the offense are determined either by the COMMON LAW or by the statute defining it. In some jurisdictions, the necessary elements are an unlawful assembly, the intent to provide mutual assistance against lawful authority, and acts of violence.