Revolutionary years

In 1775, Lambert returned again to the colonial Assembly. He also advanced in the militia, and was named captain of one of the companies raised in the city. Then, in the spring of 1776, he played a prominent role in the call for a state Constitutional Convention. He was named as a delegate, but attended only the first few meetings, as military duty called him away.

In January 1776, Cadwalader had been promoted to lieutenant colonel of the 3rd Pennsylvania Battalion of the Continental Army. Late in the summer, he was in New York to aid that city's defense. He began work on building the defenses at Fort Washington in August. After the Battle of Brooklyn, he worked with George Washington to set up defenses on the Brooklyn Heights, but they were forced to withdraw to Manhattan on August 30, because the British had overwhelming numbers.

The 3rd Pennsylvania returned to the defense of Fort Washington. At the beginning of the battle for the Fort, on November 15, Cadwalader was holding the old line on the Harlem Heights. Facing two British regiments, with three more landed to their rear, the Americans were forced to withdraw to the fort. When Colonel Magaw surrendered the fort on the next day, Cadwalader was among those taken prisoner. He was soon released, after giving his parole to British General Howe. Lambert's quick release was partly due to the consideration that his father, Dr. Thomas Cadwalader, had shown to General Richard Prescott as a prisoner of war in Philadelphia in 1776.

Early in 1777, Cadwalader was named colonel and commander of the 3rd Battalion, now called the 4th Pennsylvania Regiment. He declined to take up the assignment because he was on parole and could not serve until exchanged. He was carried on the rolls for almost two years, but a suitable exchange was never arranged. Finally, after officer exchanges broke down, Washington accepted his resignation on January 29, 1777.

When the British occupied Philadelphia in 1777, he withdrew to his father's property near Trenton, New Jersey. This home, called "Greenwood", would be his residence for the rest of his life.

Later life

In 1784, New Jersey selected him as a delegate to the Continental Congress. He would serve there for the remaining life of that institution, being returned each year until 1787. When the new government was established for the United States, Cadwalader was a Federalist in national politics. He was elected to the U.S. Congress twice, in 1788 and 1792.^[4]

Although eligible, Cadwalader did not join The Society of the Cincinnati as an original member when it was established in 1783. He did however qualify for membership and became eligible for representation by a living descendant after the "Rule of 1854" was adopted by the Society as a way to revive the membership.^[5][6]