1775, Washington appointed him to become the army's first quartermaster general, under order of Congress. Although it has been said that he was good at the job despite preferring to be on the front lines, questions were raised regarding his failure to properly supply Washington and the troops at Valley Forge, alleging that he had instead warehoused and sold supplies intended for Valley Forge to the highest bidder. Reportedly, after Washington confronted him about this, Mifflin asked to be relieved as quartermaster general but was persuaded to resume those duties because Congress was having difficulty finding a replacement. Mifflin's leadership in the Battle of Trenton and the Battle of Princeton led to a promotion to major general. In Congress, there was debate regarding whether a national army was more efficient or whether the individual states should maintain their own forces. As a result of this debate the Congressional Board of War was created, on which Mifflin served from 1777 to 1778. He then rejoined the army but took little active role, following criticism of his service as quartermaster general. He was accused of embezzlement and welcomed an inquiry; however, one never took place. He resigned his commission, but Congress continued to ask his advice even after accepting his resignation. Political career Prior to American independence, Mifflin was a member of the Pennsylvania Provincial Assembly (1772–1776). He served two terms in the Continental Congress (1774–1775 and 1782–1784), including seven months (November 1783 to June 1784) as that body's presiding officer. Mifflin's most important duty as president was to accept on behalf of Congress the resignation of General George Washington on December 23, 1783. After the war, the importance of Congress declined so precipitously that Mifflin found it difficult to convince the states to send enough delegates to Congress to ratify the Treaty of Paris, which finally took place on January 14, 1784, at the Maryland State House in Annapolis. He also appointed Thomas Jefferson as a minister to France on May 7, 1784, and he appointed his former aide, Colonel Josiah Harmar, to be the commander of the First American Regiment. Mifflin later served as a delegate to the United States Constitutional Convention in 1787. He was a signatory to the Continental Association and the Constitution. He served in the house of Pennsylvania General Assembly (1785–1788). He was a member of the Supreme Executive Council of the Commonwealth of Pennsylvania, and