SWAT units have been integral units within law enforcement agencies since ______.

SWAT units, or Special Weapons and Tactics teams, emerged as a formalized component of law enforcement agencies in the 1970s. This development was largely a response to increasing violence, particularly incidents involving armed confrontations and hostage situations. The establishment of SWAT teams aimed to provide trained officers who could handle high-risk scenarios more effectively than standard patrol units.

The 1970s marked a crucial period for the deployment of tactical units, particularly with events such as the rise of organized crime and the need to combat domestic terrorism. The Los Angeles Police Department is often credited with creating the first SWAT team in this era, pioneering a model that many agencies across the country would later adopt. This historical context reinforces the significance of the 1970s as the foundational period for SWAT operations within law enforcement strategies, making this the correct choice.