Article II and the 25th Amendment establish procedures for the Vice President to assume presidential powers. Section 1 of the 25th Amendment clarifies that when a President is removed from office, dies, or resigns, the Vice President immediately becomes President, not merely Acting President. This codified longstanding historical practice dating to John Tyler''s 1841 succession after William Henry Harrison''s death. Nine vice presidents have succeeded to the presidency: Tyler, Fillmore, Andrew Johnson, Arthur, Theodore Roosevelt, Coolidge, Truman, Lyndon Johnson, and Ford. The 25th Amendment also addresses temporary transfers of power during presidential disability. Section 3 allows presidents to voluntarily transfer authority to the Vice President by written declaration to congressional leaders, making the Vice President Acting President until the President declares ability to resume duties. Presidents have invoked Section 3 four times, all for brief medical procedures under anesthesia. Section 4 permits the Vice President and Cabinet majority to declare a President unable to discharge duties, immediately making the Vice President Acting President. If the President contests, Congress decides, requiring two-thirds of both chambers to maintain the Vice President as Acting President.