As the University of Virginia commencement speaker in June 1866, Stuart lamented the end of Old Virginia. He also opposed Congressional Reconstruction. In 1866, Stuart was a delegate to the National Convention of Conservatives at Philadelphia. In 1867, Stuart criticized the Virginia Constitutional Convention of 1868, which was elected with universal suffrage and included black delegates. Shortly after it convened, Stuart became chairman of the Committee of Nine, which lobbied the new president Ulysses S. Grant, and managed to secure separate votes for the new state constitution, which passed overwhelmingly, and anti-Confederate measures, which failed. Thus, Virginia was restored to the Union in 1870. Augusta County voters again elected Stuart to represent them in the Virginia General Assembly in 1873, and he served on the Committee on Finance. His re-election was contested, but he won the second vote and served from 1874 to 1877.