With Vice President Joe Biden announcing he would not run for President, due to bad timing to announce caused by the family tragedy of the loss of his son Beau Biden in May, it adds to the reality that any Vice President has great odds against him if he wishes to use the Vice Presidency as a launching pad for the Presidency.
Only four Presidents have been able to run from the Vice Presidency for President and triumph, with all but one in the first 50 years of the Republic, as follows:
John Adams 1796
Thomas Jefferson 1800
Martin Van Buren 1836
The other President is George H. W. Bush in 1988.
Never until the 1940s and after did a sitting Vice President ever get considered at all for the Presidency, other than if he succeeded the President by natural death or assassination.
So we had Vice President John Nance Garner trying to win the 1940 Democratic Presidential nomination, but unfortunately for him, Franklin D. Roosevelt decided to seek a third term.
In 1948, former Vice President Henry Wallace in the third term of FDR tried for the Presidency as a third party candidate (Progressive Party), fighting against fourth FDR term Vice President Harry Truman, who had succeeded FDR upon his death in 1945.
Alben Barkley, Vice President under Truman in his full term, tried to win the 1952 Democratic Presidential nomination, but his age was used against him, which may have been good, since Barkely died during the next term when he would have been President.
Richard Nixon ran for President to succeed Republican Dwight D. Eisenhower in 1960, but lost in a close election to John F. Kennedy. Of course, Nixon won eight years later, being the first Vice President elected since Martin Van Buren in 1836, but eight years after.
Hubert H. Humphrey ran for President in 1968 to succeed Lyndon B. Johnson, but was defeated by Nixon, and tried for the nomination again in 1972, but failed to be selected as the Presidential nominee.
Walter Mondale ran for President in 1984 after he and Jimmy Carter were defeated in 1980 for a second term, but lost to Ronald Reagan.
George H. W. Bush is the only exception to this reality, winning in 1988 after serving two terms as Vice President under Ronald Reagan.
Dan Quayle tried for the Republican nomination in 1996 after serving one term under George H. W. Bush, but flopped badly.
Al Gore ran for President in 2000 after two terms as Vice President under Bill Clinton, and of course won the popular vote, but lost the hotly contested electoral vote in Florida, with Supreme Court intervention, leading to the victory of his opponent George W. Bush.
Dick Cheney had tried briefly for the Presidency in 1996, but when he was Vice President under George W. Bush for two terms, his health was fragile and he chose not to try for the Presidency in 2008.
And now Joe Biden, after two terms as Vice President under Barack Obama, has reluctantly decided not to run for President in 2016, due to the tragic death of his son Beau in May, and the grieving period preventing organization of a Presidential campaign.
So the record shows, with the exception of Richard Nixon eight years later and George H. W. Bush, no Vice President has succeeded in modern times to the Presidency unless the President died in office, or with the case of Richard Nixon resigning, led to Gerald Ford succeeding him in the White House.