He was a prominent member of the congress of 1774, that convened at Philadelphia. From that time to the peace of 1783, he was a member of the continental congress, and the only one who served during the whole time. He was a strong advocate for the declaration of independence, and most willingly affixed his signature to that sacred instrument. When it came up for final action, so anxious was he that it should pass _unanimously_, that he sent an express after Cæsar Rodney, one of his colleagues, the other, Mr. Read, having manifested a disposition to vote against it. Mr. Rodney arrived on the 4th of July, just in time to give his vote in favour of the important measure, and thus secured its unanimous adoption. Notwithstanding the arduous duties that devolved on Mr. M’Kean, as member of congress, member of several committees, and chief justice of Pennsylvania, all of which he discharged satisfactorily—so ardent was his patriotism, so devoted was he to promote the cause he had nobly espoused, that he accepted a colonel’s commission, and was appointed to the command of a regiment of associators, raised in the city of Philadelphia, and marched to the support of Gen. Washington, with whom he remained until a supply of new recruits was raised. During his absence, his Delaware constituents had elected him a member of the convention to form a constitution. On his return he proceeded to New Castle, and, in a tavern, without premeditation or consulting men or books, he hastily penned the constitution that was adopted by the delegates. Understanding the wants and feelings of the people, well versed in law and the principles of republicanism, and a ready writer, he was enabled to perform, in a few hours, a work that, in modern times, requires the labours of an expensive assembly for nearly a year. How changed are men and things since the glorious era of ’76! How different the motives that now impel to action, and how different the amount of labour performed in the same time and for the same money. Then all were anxious to listen! now nearly all are anxious to speak. Then, legislators loved their country _more_, and the loaves and fishes _less_, than at the present day. On the 10th of July, 1781, Judge M’Kean was elected president of congress, which honour he was compelled to decline, because his duties as chief justice of the Supreme Court of Pennsylvania would necessarily require his absence some part of the time during the session. He was then urged to occupy the chair until the first Monday of November, when the court was to commence. To this he assented, and presided until that time, with great credit to himself and to the satisfaction of the members of that august body. On his retiring from the chair, the following resolution was unanimously passed on the 7th of November, 1781: