In response to the UT Tower incident, along with several other major events including the Watts riots in Los Angles, special tactical police units (SWAT teams) were formed in the late 1960s and early 1970s. Retired Los Angeles Chief of Police Daryl Gates is considered the "Father of SWAT" by most in the tactical community. his forward thinking let to the development of police tactical units across the USA. Many of his ideas are still in place today.
As tactical units began to flourish in the police community in the 1970s and 1980s, there began a gentle erosion of the responsibilities of patrol officers. the law enforcement profession in general began an era of specialization into such areas as narcotics, vice, street response units, evidence collection teams, special investigative units, and tactical units. in agencies with specialized tactical units, patrol officers and other first responders became accustomed to responding containing the situation, and then calling for the SWAT team. this response became the standard for almost all agencies that had a SWAT team within 100 miles. Officers and field supervisors had little or no discretion to act differently. more importantly, they had no training to act differently.
there are probably many instances over the past 40 years where the first responding officers, had they been empowered by police administrators and had the proper training, could have intervened and stopped a critical situation prior to the SWAT team's arrival.
However, no single event polarized the public and the law enforcement profession regarding this issue as did the events in Littleton, Colorado, on April 20, 1999.