The Secretary of State serves at the will of the President of the United States, and its ranks have included future Presidents; Presidential candidates who were Secretary of State and later lose the Presidency; Presidential losers who then become Secretary of State; and Presidential contenders who do not get nominated for President, but later become Secretary of State. The Secretary of State also is often a great public figure who becomes notable for his background, without having sought the Presidency. Witness the following:
Presidents who were Secretary of State—Thomas Jefferson, James Madison, James Monroe, John Quincy Adams, Martin Van Buren, James Buchanan
Presidential candidates who were Secretary of State and later lose the Presidency—Henry Clay, James G. Blaine
Presidential Losers who then become Secretary of State—Henry Clay, Daniel Webster, Lewis Cass, James G. Blaine, William Jennings Bryan, Charles Evans Hughes, John Kerry
Presidential contenders who do not get nominated for President, but later become Secretary of State—John C. Calhoun, William Seward, Edmund Muskie, Hillary Clinton.
Great public figures notable for their background, without having sought the Presidency, but become Secretary of State—John Marshall, Edward Everett, Hamilton Fish, William Evarts, Richard Olney, John Sherman, John Hay, Elihu Root, Robert Lansing, Frank Kellogg, Henry Stimson, Cordell Hull, James F. Byrnes, George C. Marshall, Dean Acheson, John Foster Dulles, Dean Rusk, Henry Kissinger, Cyrus Vance, George P. Shultz, James Baker, Warren Christopher, Madeleine Albright, Colin Powell, Condoleezza Rice.
So 42 of the 68 people who have served as Secretary of State are prominent in American history, while some of our 43 Presidents have NOT been notable in their careers or in their Presidency!