What Does the Vice President Do, Anyway?

In the vice presidential debate Thursday, Republican candidate Sarah Palin differed from Democratic pick Joe Biden on the topic of exactly what the vice president's job is or ought to be.

Palin said she would continue with current Vice President Dick Cheney's tactic of working in both the executive and legislative branches.

"I'm thankful the Constitution would allow a bit more authority given to the vice president if that vice president so chose to exert it in working with the Senate," she said during the debate.

Biden countered that Cheney had overstepped the bounds of his role, calling him the "most dangerous vice president in U.S. history." Biden insisted the vice president’s only authority in the legislative branch is to vote in the Senate in the event of a tie.

Which all raises the question, just how much power does the veep officially have?

The Constitution gives the vice president the role of presiding over the Senate, and voting in the Senate if there is a tie. The vice president's only other formal responsibility is taking over the presidency if the president dies.

"That's about it in terms of the formal role," said Paul Brace, a political scientist at Rice University in Texas who researches presidential history. "For many years, there was such lopsided control of the Senate, the tie-breaking vote never really came into play. Traditionally it’s a pretty meaningless role. It's not something that allows you to exercise a lot of power."

Presiding over the Senate means basically running the debates and overseeing operations there, Brace said. Many veeps have skipped even that responsibility, he said, only showing up on the rare occasions a tie-breaker is needed.

Historically, the vice president's level of government involvement has varied. More recently, second-in-commands have taken a more hands-on role, Brace said, with Al Gore, and perhaps Cheney, being some of the most active.

John Nance Gardner, Franklin D. Roosevelt's VP, was one of the least involved, and famously said the vice presidency wasn't worth "a warm bucket of spit." (Reporters allegedly changed the spelling of the last word for print).

"The role is ambiguous, it's changed over time," Brace told LiveScience. "Traditionally, they didn’t give speeches, they didn't travel, they were figureheads. They were lying in wait for the presidency. It's more important now because presidents are seeking any way they can to mobilize public support. Vice presidents can be an instrument in their efforts to reach out to the public."

Often, veeps would only emerge from obscurity if they went on to take over the presidency, either through assuming the office in the event of the president's death, or running and winning after the president had served his term.

Overall, 14 vice presidents have gone to on to become president. John Adams, George Bush, Thomas Jefferson, Martin Van Buren and Richard Nixon were elected president after being VP. Andrew Johnson, Lyndon B. Johnson, Theodore Roosevelt, Harry S. Truman, John Tyler, Chester A. Arthur, Calvin Coolidge, Millard Fillmore and Gerald R. Ford assumed the presidency after the president either died a natural death, was assassinated or resigned.

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Editor's Note: This story was corrected to reflect the circumstances of Richard Nixon's route to the presidency.