Of course, Michelle Obama has her own reputation as a liberal dispenser of hugs wherever she goes.
The barriers between presidential candidates and the public gradually have gotten higher in the years since the assassination of John F. Kennedy and the attempts on the lives of Gerald Ford and Ronald Reagan.
Former President Bill Clinton chafed at the restrictions and still managed to maintain plenty of contact with people.
But Shuster says the restrictions aren't necessarily a bad thing in the view of many candidates, who don't always want to chat up every voter in sight.
"I honestly feel like they like the fact that the Secret Service has not permitted them to do things like that," he says. "It could go on forever."
John McCain, the GOP nominee in 2008, was known to discreetly pump some hand sanitizer after making contact with voters. Secret Service agents carried some for Clinton, too. Candidates want the public's votes — not their germs.
In the case of Van Duzer's powerlift of the president, the pizza man said Secret Service agents told him he "was all right as long as I didn't take him away."
Secret Service spokesman Ed Donovan said that when candidates are out in public, agents "are constantly making assessments on the appropriateness of the behavior of the people" around them. He added that in this case, the agents "felt that the behavior was appropriate and was consistent with the event."
After Van Duzer brought the president back down to earth, Obama diplomatically declared, "Look at that!"
But Glass, the body language expert, says Obama didn't look all that pleased.
"That was a little overboard," she says.
Van Duzer said Wednesday he's gotten a crush of supportive calls and visits since critics online pounced on him for his bear hug — and support of Obama. He said he'd be happy to campaign for the president if asked.
As for Biden, he proffers both one-armers and two-arm hugs, and high-fives and kisses and shoulder rubs of people of all ages and both genders. And of course he slaps a few backs, too.
"He wants to fit in so badly, it's kind of a like a puppy that just wants to belong," says Glass. "He's overshooting the mark."
Associated Press writers Philip Elliott, Matthew Daly and Laurie Kellman contributed to this report.
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