Sarah Palin and the Presidential Succession Issue

John McCain's choice of Alaska Gov. Sarah Palin as his vice presidential running mate has energized the Republican right. But her nomination also has raised questions about whether Palin, governor for less than two years, is too inexperienced and untested to be a heartbeat away from the presidency under a 72-year-old commander in chief who has a history of cancer.

These concerns might seem macabre, but they are not misplaced. History shows that it's far from unusual for a vice president to step into the top job. It has happened nine times so far, and since 42 individuals have served as chief executive, the rate of "accidental presidents" is sobering—more than 20 percent.

A history of presidential succession is illuminating. John Tyler became the first accidental president in April 1841 when William Henry Harrison died at age 68. Harrison, the ninth chief executive, caught a cold that became pneumonia. He was in office only a month—the shortest presidential tenure ever.

A total of eight presidents, including Tyler, took over after the death of a predecessor, including some of the greatest leaders, such as Theodore Roosevelt in 1901 and Harry Truman in 1945. But some "accidentals" have been among the most mediocre or, frankly, among the worst chief executives ever. They include Andrew Johnson, who succeeded Abraham Lincoln in 1865, and Millard Fillmore, who took over after Zachary Taylor's death in 1850. Gerald Ford took office after his predecessor, Richard Nixon, resigned in 1974. He had mixed success.

Illness and assassination. Four vice presidents took over after their predecessors died of natural causes. They were Tyler in 1841, Fillmore in 1850, Calvin Coolidge in 1923, and Truman in 1945. An additional four succeeded to the presidency because of assassination—Andrew Johnson in 1865, Chester Arthur in 1881, Roosevelt in 1901, and Lyndon Johnson in 1963.

Several attributes distinguish a successful accidental president from a failure. Unfortunately for Palin, substantial government experience plays a role in helping a new leader take over successfully. Theodore Roosevelt, for example, held a variety of public-service jobs, including governor of New York and assistant secretary of the Navy. Truman had been a veteran senator from Missouri before Franklin Roosevelt tapped him as his No. 2.

But other factors seem even more important, such as the ability to learn quickly and the capacity to understand the nation's mood and to act on it. Lyndon Johnson immediately understood the zeitgeist when John F. Kennedy was assassinated in 1963, and he embraced JFK's activist legacy to move a massive legislative agenda to passage. But then Johnson, formerly a powerful Senate leader, misread public opinion and pushed too far. He ran aground on the shoals of the unpopular Vietnam War and social policies that seemed extreme to many moderate voters. Johnson became so unpopular that he declined to seek re-election in 1968.

In some ways, the best predictor of success by an accidental president is the ability to seize the moment. "Accidental presidents experience their own macabre version of a presidential honeymoon with Congress since a grieving public regards partisanship as inappropriate," political scientist Philip Abbott writes in Accidental Presidents: Death, Assassination, Resignation, and Democratic Succession.

What a new president does in the initial months after taking office is all important because that's when the new leader tends to have maximum public sympathy and support. "All accidental presidents are prisoners of time," Abbott writes. "Their decisions must not only be correct strategically but they also must be executed at the exact right moment." In most cases, he writes, "[Theodore] Roosevelt showed an almost uncanny ability in this regard."

Today, voters may ponder whether Sarah Palin and Joe Biden are up to the job. Palin seems to be a quick study and has charisma. But does she have a good sense of timing, and is she decisive? Is she in tune with the nation's mood? Is her background in Alaska too limited in a nation as diverse and turbulent as modern America? And what about Biden, the running mate of Democrat Barack Obama? Is he a prisoner of his three decades in the Senate, unable to connect with Americans who want an outsider to shake things up? Is he too locked into liberal orthodoxy to try new approaches? What about his sense of timing?