The political buzz consuming Washington's steamy summer has nothing to do with stock market jolts or even the Iran nuclear deal -- the name on everyone's lips is Joe Biden.

Will the veep launch another White House run?

Speculation has intensified in recent weeks that President Barack Obama's wingman is more likely than not to throw his hat into the presidential ring for the third time and challenge Hillary Clinton, the former secretary of state.

Biden would undeniably enter the race as the underdog. Clinton has amassed an impressive war chest, built a comprehensive and diverse campaign staff and has been seen as the party's frontrunner for more than a year -- all clear hurdles for the vice president.

Some have described the 2016 Democratic nomination, and even the election itself, as hers to lose. Many insist it is her turn, with her historic bid to become America's first female president losing out in 2008 to Obama's own historic run to be the first black commander-in-chief.

But Clinton has been unable to shake the scandal swirling around her use of a private email server while at the State Department.

Her favorability and trust ratings are trending downward, according to polls. Liberal Senator Bernie Sanders is meanwhile making substantial cuts into her lead, and Republicans are mounting a fierce anyone-but-Clinton effort.

With no Democratic candidate inspiring much passion other than Sanders, a self-described democratic socialist, Biden could well see an opening as a safety net for a party worried about a possible Clinton implosion.

- Presidential 'aptitude' -

The "will he or won't he" speculation reached new heights when White House spokesman Josh Earnest noted Obama's fondness for his number two.

"The president has indicated his view that the decision that he made, I guess seven years ago now, to add Joe Biden to the ticket as his running mate was the smartest decision that he had ever made in politics," Earnest told reporters Monday.

"And I think that should give you some sense of the president's view of Vice President Biden's aptitude for the top job."

Earnest would not be drawn on whether Obama would back Biden over Clinton, or vice versa, but he said the president could ultimately endorse a candidate.

"I wouldn't rule out the possibility of an endorsement in the Democratic primary," Earnest said.

Biden huddled at the weekend with Senator Elizabeth Warren, a power broker among American liberals. And Obama, who lunched with Biden Monday, has given his deputy his "blessing" to run and would not counsel against it, CNN quoted a Democratic source as saying Tuesday.

The network also reported that Biden and his advisors hosted former Obama White House advisors Anita Dunn and Bob Bauer at his residence late Monday.

Biden trails Clinton by a considerable margin in polling -- 49 percent to 12 percent, according to a RealClearPolitics aggregate.

But a recent Quinnipiac University poll in three swing states shows the vice president doing as well as Clinton against Republicans in general election matchups, including winning against current Republican frontrunner Donald Trump.

Biden, 72, has previously said he would make a decision on entering the 2016 race by summer's end, about a month from now.

It appeared increasingly likely that he is assessing whether he and his family -- still grieving the death of Biden's son Beau -- are emotionally ready for a presidential bid.

California Governor Jerry Brown said Sunday on NBC's "Meet the Press" that Biden should give "very serious consideration" to a presidential campaign.

The first votes in the primaries will not be cast until early February, but Biden likely would need to jump in soon if he were to make a viable run.

The first Democratic primary debate is scheduled for October 13.