Chandler enlisted in the
New York National Guard as a
lieutenant. By 1916, he had been promoted to the rank of
major. Chandler served with the National Guard in 1917, when his unit was called up to respond to an invasion on the southern border with Mexico related to forces in its civil war. Shortly after returning to the state from the
Pancho Villa Expedition, Chandler was tapped by his friend and
New York Governor Charles S. Whitman to head and organize the
New York State Police. Chandler coined the term "New York State Trooper." Contrary to the norms of the time, he required that troopers carry their weapons exposed on the outside of their uniforms. More positively, he instituted rigorous processes for screening, training, and education of the force. Chandler also established the New York State School for Police, which emphasized legal training. This became a standard for police forces in the United States. ==Retirement==