Following Independence Ewing aligned himself with wealthy business interests, as a Republican and Anti-Constitutionalist (the latter movement being opposed to the unicameral legislature of Pennsylvania’s 1776 Constitution), and later as a Federalist. In 1781 he won a seat on the Supreme Executive Council of Pennsylvania. On November 7, 1782, Ewing was elected Vice-President of Pennsylvania, earning thirty nine votes to the thirty four won by the incumbent, James Potter. (The position of Vice-President is analogous to the modern office of Lieutenant Governor.) He was unanimously reelected on November 6, 1783, and served until November 6, 1784, when he was succeeded by James Irvine. At one day short of two years, his vice-presidential term was one of the longest in the history of that short-lived office.
