Joe Biden is flying high as speculation swirls around his joining the race for the White House.
But while the vice president may have soaring popularity in the polls right now, the true test of whether he can keep his favorables afloat comes after he becomes a candidate.
The high favorable ratings for Biden — topping leading Democratic candidates Hillary Clinton and Bernie Sanders — in the latest NBC/Wall Street Journal poll are encouraging for him as he weighs his decision.
Eight years ago, when the Delaware senator was running for president, it was a much different story. He wasn't necessarily liked or disliked — people just didn't know him. That changed after then-Sen. Barack Obama picked Biden as his running mate. Ahead of the 2008 election, Biden's popularity ticked up.
And throughout the Obama administration, the trajectory of Biden's favorability closely tracked the president's — it dipped in 2010 ahead of the GOP congressional wave, rose back up as the economy improved and stayed roughly even until last year.
But over the past few months, Biden's numbers have been rising again, along with the clamoring for him to enter the 2016 race. Some of that, of course, comes in the face of the tragedy he and his family have faced — the death of his eldest son, Beau, in May to brain cancer.
Biden has persevered in the face of his very public grief, and that seems to endear him even more to the public. In raw interviews, Biden has shown an authenticity that has won him new admirers even as it reminded old friends of their fondness. Even though he may have seemed like a bumbling sidekick who sometimes stuck his foot in his mouth, at least people never doubted he was being honest and genuine.
And many have been reminded of why they liked Biden in the first place — his blue-collar roots can appeal to the core of the Democratic party base, soothing worries that Clinton is slipping with that demographic as her campaign has struggled.
"I think there is a likability factor for Joe Biden," said Iowa pollster J. Ann Selzer, whose Bloomberg News survey last month found the vice president had an 80 percent favorability rating among Democrats — compared to 70 percent for Clinton and 56 percent for Sanders.
"In a campaign that is putting a lot of value on what people perceive as authenticity, they get who he is," Selzer said of voters' opinions of Biden. "He's not a calculating person, as far as the public can see."
But Biden, of course, is not an official candidate yet, continuing to drag out a self-imposed summer deadline. The Bloomberg survey found that 47 percent of all voters — Republicans, Democrats and independents — would like for him to run.
If he does pull the trigger, there will be a much different kind of scrutiny. While some candidates have a honeymoon period, others can nosedive under attacks and pressures of the trail. And history hasn't been kind to late entrants, either.
"He will step in probably with a halo, and he'll be beat up — and he'll survive or he won't," Selzer said.
The punches are already beginning from the Clinton camp, too, as they are beginning to subtly point out their past differences on liberal policies.
Democratic pollster Mark Mellman said it's impossible to predict what will happen to a potential candidate who becomes an actual candidate. But Biden still has plenty of strengths that set him apart from lesser-known candidates who might collapse under the pressure.
"In some sense people have gotten to know him better due to this horrific tragedy than they had before. He is well liked, and that positive feeling people have is deeper than the feelings than they had earlier, which were based on much less information," said Mellman.
"At this point, he's certainly the most popular candidate out there, and it's hard to ignore. It may or may not last but it's hard to ignore."