When the Assembly of the Lower Counties declared its separation from the British government on June 15, 1776, it created a Council of Safety to run the newly independent state when the Assembly was not in session. It consisted of five members from each county. McKinly was one of those representing New Castle County, and was elected President of the Committee. Then when Delaware elected its first House of Assembly in October 1776, he was again elected to represent New Castle County in the 1776/77 session, and was chosen by that body as its Speaker.