Vice-president Joe Biden has made his most revealing comments on whether he will mount a third presidential bid, saying the decision rests on whether his family are up to it following the death of his eldest son.
Speculation has been mounting as to whether Mr Biden will run with Democratic frontrunner Hillary Clinton slipping in the polls as a result of her handling of the controversy over her use as a private email address as secretary of state from 2009 to 2013.
The vice-president, who trails Mrs Clinton in the polls by more than 30 points, has questioned whether his family can handle a taxing national campaign so soon after the death of his son Beau Biden, the former attorney general of Delaware, in May. Mr Biden died of brain cancer at the age of 46 leaving behind a young family.
“The most relevant factor in my decision is whether my family and I have the emotional energy to run,” said the vice president during a questions-and-answers session at a synagogue in Atlanta.
Mr Biden, who served in the Senate from 1973 to 2009, ran for the Democratic presidential nomination in 1988 and again in 2008 but dropped out of both races early. A third run would depend on whether he and his family have the energy to mount another bid, he said.
“Can I do it, can my family? There is no way to put a timetable on that. If I can reach that conclusion that we can do it, in a fashion that would still make it viable, I would not hesitate to do it,” he said.
Reports suggested that Beau Biden urged his father to put his name forward as a candidate while he was dying of cancer.
Mr Biden has been seriously considering a presidential bid, canvassing the views of advisers and meeting key figures, including Massachusetts senator Elizabeth Warren and AFL-CIO union leader Richard Trumka who hold sway among grassroots Democrats.
Democrats, concerned about Mrs Clinton’s lawyerly response to questions about her emails and her falling approval ratings on the issues of honesty and trustworthiness, are looking to a viable alternate candidate should the scandal continue to plague the former first lady.
Mrs Clinton's campaign manager Robby Mook said on Thursday that Mr Biden would be "a commanding presence" if he became a candidate and would "certainly shake up the dynamics quite a bit."
The former secretary of state told NBC News on Friday that she was “sorry” that there had been so much confusion over her use of a private email server as secretary of state but would not apologise for the decision not to use an official email for government business.
The controversy shows no sign of abating, particularly after a former Clinton staff member Bryan Pagliano, who oversaw her email server, said he planned to invoke his Fifth Amendment right not to answer incriminating questions about it before a congressional panel.
A House of Representatives committee is investigating the attack on the US diplomatic outpost in Benghazi, Libya during Mrs Clinton's time at the State Department.