Sen. Marco Rubio of Florida and other ambitious Republicans eyeing a possible invitation to be Mitt Romney's running mate might want to keep 1920 in mind.
That was the last time the losing vice presidential nominee was a politician skillful and lucky enough to eventually become president.
His name? Franklin D. Roosevelt.
So one takeaway for this year's much-talked-about group of potential vice presidential candidates is simply this: If you hope to be president one day, accepting the No. 2 spot is a pretty good deal if the ticket wins - and a possible path to political obscurity if it loses.
Of the dozen presidents since FDR, five were former vice presidents. (Harry S. Truman, Lyndon B. Johnson, Gerald R. Ford and George H.W. Bush moved directly into the Oval Office; Richard M. Nixon had to wait eight years).
A few former vice presidents won their party's presidential nomination but lost the general election. They include Hubert H. Humphrey, Walter Mondale and Al Gore. But the losing vice presidential nominee has tended to join a more frustrated list of people who at one time or another sought the presidency. They include John R. Edwards, Joe Lieberman, Jack Kemp, Lloyd M. Bentsen and Edmund S. Muskie.
Mr. Romney hasn't locked up the GOP presidential nod, but he's on his way. Speculation about his choice for a running mate, meanwhile, is rising.
Most often mentioned are younger politicians who have expressed presidential ambitions themselves or had others do it for them. They include Mr. Rubio, Louisiana Gov. Bobby Jindal and Rep. Paul Ryan of Wisconsin, all in their early 40s; New Jersey Gov. Chris Christie, 49; Sen. John Thune of South Dakota, New Mexico Gov. Susana Martinez, and former Minnesota Gov. Tim Pawlenty, all in their early 50s; and Virginia Gov. Bob McDonnell and Sen. Rob Portman of Ohio, in their mid-to-late 50s.
All are younger than Mr. Romney, 65. They could be well-positioned to run for president in 2016 if Mr. Romney loses this fall to President Obama, or in 2020 if Mr. Romney wins.
The question they may have to ask themselves is this: Is it worth joining Mr. Romney's ticket, given that the November election is likely to be close and Mr. Obama is a well-financed, experienced campaigner?
Roosevelt was a 38-year-old assistant secretary of the Navy when he became James M. Cox's running mate in 1920. Warren G. Harding won easily, Cox was forgotten, and Roosevelt 12 years later won the first of his four terms as president.
It's certainly an honor to be asked to run for vice president of the United States. It's also a gamble.