Philadelphia, McKean remained the effective leader for American independence in Delaware. Along with Read and Caesar Rodney, he was one of Delaware's delegates to the First Continental Congress in 1774 and the Second Continental Congress in 1775 and 1776. Being an outspoken advocate of independence, McKean was a key voice in persuading others to vote for a split with Great Britain. When Congress began debating a resolution of independence in June 1776, Rodney was absent. Read was against independence, which meant that the Delaware delegation was split between McKean and Read and therefore could not vote in favor of independence. McKean requested that the absent Rodney ride all night from Dover to break the tie. After the vote in favor of independence on July 2, McKean participated in the debate over the wording of the official Declaration of Independence, which was approved on July 4. A few days after McKean cast his vote, he left Congress to serve as colonel in command of the Fourth Battalion of the Pennsylvania Associators, a militia unit created by Benjamin Franklin in 1747. They joined General George Washington's defense of New York City at Perth Amboy, New Jersey. Being away, McKean was not available when most of the signers placed their signatures on the Declaration of Independence on August 2, 1776. Since his signature did not appear on the printed copy that was authenticated on January 17, 1777, it is assumed that he signed after that date, possibly as late as 1781. In a conservative reaction against the advocates of American independence, the 1776-1777 Delaware General Assembly did not reelect either McKean or Rodney to the Continental Congress in October 1776. However, the British occupation after the Battle of Brandywine swung opinions enough that McKean was returned to Congress in October 1777 by the 1777–1778 Delaware General Assembly. During that time, he was constantly pursued by British forces. Over the course of the following years, he was forced to relocate his family five times. He served continuously in the Congress until February 1, 1783. McKean helped draft the Articles of Confederation and voted for their adoption on March 1, 1781. When poor health caused Samuel Huntington to resign as president of Congress in July 1781, McKean was elected as his successor. He served from July 10 to November 4, 1781. The position was mostly ceremonial with no real authority, but the office required McKean