WASHINGTON (AFP) - US Vice President Joe Biden raised the possibility of a fresh tilt at the White House in 2016 in an interview with GQ magazine published on Thursday.
The 70-year-old former senator, who has already made two unsuccessful bids for the presidency in 1988 and 2008, suggested he could run for the Democratic nomination if his health allowed it.
"I can die a happy man never having been president of the United States of America," he told GQ. "But it doesn't mean I won't run."
President Barack Obama chose Mr Biden as his running mate after winning the epic battle for the Democratic nomination in 2008.
The former Delaware senator, who will be 74 by the time of the next presidential election, said his "energy" would be a key factor in any decision to run.
"The judgment I'll make is, first of all, am I still as full of as much energy as I have now - do I feel this?" Mr Biden said.
"Number two, do I think I'm the best person in the position to move the ball? And, you know, we'll see where the hell I am." If Biden made a successful bid for the presidency, he would be the oldest first-term occupant of the White House.
Ronald Reagan was 69 years old when he took office, and was 73 when he was re-elected four years later.
Mr Biden could also face a challenge from Hillary Clinton, Mr Obama's closest rival in the 2008 nomination battle who is being heavily tipped as a possible candidate.