Why the Palin Pick Matters

There have been 43 US presidents in our nation's history. Nine of them ascended from the vice presidency to the Oval Office due to the sitting president's incapacitation (for whatever reason). That's 21%.

John Dean has more here.

In truth, the vice president of the United States is important for only one reason: He or she will become president of the United States upon the death, incapacity or resignation of the president. Nine times in our history, vice presidents have succeeded to the presidency: John Tyler (1841), Millard Fillmore (1850), Andrew Johnson (1865), Chester A. Arthur (1881), Theodore Roosevelt (1901), Calvin Coolidge (1923), Harry Truman (1945), Lyndon Johnson (1963) and Gerald Ford (1974).