Joe Biden 'actively considering' challenging Hillary Clinton

Speculation about Joe Biden possibly entering into the 2016 presidential race reached a fevered pitch over the weekend - and the vice-president and his staff have done little to tamp down the talk since then.

It all began on Saturday with a column Maureen Dowd in the New York Times, in which she recounted an impassioned request Mr Biden had received several months ago from his 46-year-old son, Beau Biden, who was dying of brain cancer.

"Beau was losing his nouns and the right side of his face was partially paralysed," she writes. "But he had a mission: He tried to make his father promise to run, arguing that the White House should not revert to the Clintons and that the country would be better off with Biden values."

Dowd has the reputation among some on the left of being a bit of a Clinton family antagonist - and armchair psychologist - so her attempt to ramp up speculation of Democratic Party looking for alternatives to former Secretary of State Hillary Clinton shouldn't come as too a much of a surprise. She also offered Howard Schultz, head of coffee shop empire Starbucks, as another possible Democratic contender.

A follow-up article by Times reporter Amy Chozick, however, added further substance to the reports that Mr Biden's people "through hushed phone calls and quiet lunches" are putting out feelers to possible campaign staffers and supporters.

ABC News reporter Cecilia Vega says one Biden adviser told her the vice-president is "90% in".

In addition, Josh Alcorn - a former senior adviser to Beau Biden - is joining Run Biden Run, an organisation that could lay the groundwork for a presidential campaign.

Official word from the Biden camp is that nothing has been decided yet - but an announcement one way or the other will likely come in early September.

According to reports, the vice-president has taken note of the controversies over Mrs Clinton's private email server while secretary of state and questions about donations to the Clinton Foundation - and the toll these stories have had on her public approval ratings.

One recent survey shows the vice-president performing better than Mrs Clinton in head-to-head matchups against possible Republican candidates.

Historically, the sitting or recently former vice-president has been at the head of the pack for his party's nomination - think Al Gore, George HW Bush, Walter Mondale or Hubert Humphrey. George W Bush's second-in-command, Dick Cheney, was the only recent notable exception.

Before he died of brain cancer, Beau Biden reportedly asked his father to run for president

It seemed for a while that Mr Biden would follow Mr Cheney's lead - he is, after all, 72 years old and would be the oldest person ever elected president if he were to win (Ronald Reagan upon his re-election in 1984 was a few months younger than Mr Biden would be).

This would mark the third time Mr Biden has sought the Democratic presidential nomination. In 1988 he was an early contender before withdrawing from the race following controversy surrounding his academic record and evidence that he plagiarised the campaign speeches of UK Labour Party leader Neil Kinnock.

Mr Biden ran again in 2008, but his candidacy was overshadowed by the Barack Obama-Hillary Clinton showdown. His foreign policy knowledge - honed from decades in the US Senate - made enough of an impression on Mr Obama, however, that he was tapped to be the then-Illinois senator's running mate - a position for which he has by all accounts performed loyally, albeit with an occasional ill-thought phrase or photo.

If the vice-president chooses to enter the race, he will undoubtedly have an uphill climb against Mrs Clinton. She's spent nearly a year assembling her campaign team, raising money and lining up support within the Democratic Party, while the vice-president has done little in the way of preparation.

What he does have, however, is high name recognition in the party and a great deal of goodwill among the Democratic rank and file, particularly since his son's death two months ago. Mr Biden has a reputation as a skilled debate and capable campaigner who can connect with working voters. He gave the most-watched speech at either of the 2012 party conventions - ahead of former President Bill Clinton, Republican nominee Mitt Romney and even Mr Obama.

Joe Biden may be just the latest vice-president to seek the Oval Office

Mr Biden's entry would undoubtedly shake up the race. If he eats into Mrs Clinton's establishment support, for instance, it could be a boon for Vermont Senator Bernie Sanders' insurgent candidacy. He's already reduced Mrs Clinton's lead to near single digits in New Hampshire, and if his true-believer base stick with him, it isn't too difficult to imagine a scenario where he pulls out a win there.

So far the Clinton campaign has responded to the Biden talk with a soft touch.

"We are not going to have any comment on Biden stories except I love the guy!" Jennifer Palmieri, Clinton's communications director, told Bloomberg News.

Perhaps not coincidentally, the Clinton campaign just announced it has a forthcoming $2 million (£1.28 million) television advertising buy in the early voting states of Iowa and New Hampshire, featuring two spots touting their candidate's personal story.

It's the largest on-air show of strength from a candidate so far in the race - and an example of just what Mr Biden could be up against if he decides to make one more try for the presidential prize.