He served longer than any president in U.S. history not elected to the office. To forestall constitutional uncertainty, Tyler immediately took the oath of office, moved into the White House, and assumed full presidential powers—a precedent that governed future successions and was codified in the Twenty-fifth Amendment. Tyler signed into law some of the Whig-controlled Congress's bills, but he was a strict constructionist and vetoed the party's bills to create a national bank and raise the tariff rates. He believed that the president should set policy rather than Congress, and he sought to bypass the Whig establishment, most notably senator Henry Clay of Kentucky. He left office on March 3, 1821, endorsing his former opponent Stevenson for the seat, and returned to private law practice full-time. On March 3, 1835, with only hours remaining in the congressional session, the Whigs voted Tyler President pro tempore of the Senate as a symbolic gesture of approval. He is the only U.S. president to have held this office.Shortly thereafter, the Democrats took control of the Virginia House of Delegates.