Thursday's Barack Obama/Joe Biden love fest birthed a deluge of tweets, several containing the same word: "bromance." Obama brought it up during the surprise medal of honor presentation for Biden himself, saying the internet was getting another chance to joke about their friendship.
Many have watched the relationship between the political pair evolve over Obama's tenure. From those tense moments in the War Room, the night Osama Bin Laden was killed:
...to the way that Biden came to bat for the president during the 2012 debate against Paul Ryan.
Bromances in the Executive Branch may be far and few, but it wasn't long ago that deep male-to-male friendships in everyday life were rare. The reason? Social norms, of course.
"A bromance describes a relationship between two men that we've been socialized to see is not at all unusual between two women," says John Alberti, author of the book "Masculinity in the Contemporary Romantic Comedy: Gender as Genre."
Alberti says male friendships turn to bromances after they've reached a certain level of emotional intimacy.
"A man being able to tell his close friend that he loves him ... it's this sort of key line to cross," Alberti says.
Bromances became more common as society changed.
"I think it's a part of a whole evolution of gender roles, really over the past half-century — particularly the last 20 or 30 years," Alberti says. "That goes along with the women's rights movement and the LGBT rights movement challenging the ways we understand gender and the idea of male dominance."
A quick Google search of the word "bromance" will result in this definition:
"A close but non-sexual relationship between two men."
But Alberti says just because one or both friends might not acknowledge their attraction doesn't mean it's not there.
"I think there can be some sexual tension," Alberti says. "I think part of the bromance is an admission that close friendships, intense relationships involve all sorts of emotions, including some that we might want to neatly box off into the non-romantic."
Alberti says there's a range of feelings involved in a bromance — and that's OK.
Vice presidential picks are rarely made because the two men share a particular affinity for each other — VPs often offer candidates a strategic advantage. John Alberti says the Obama-Biden relationship evolved beyond those of their contemporaries because President Obama exhibits more characteristics of modern manhood.
"With Biden and Obama, I think you have a president in Obama who exhibited a more evolved sense of masculinity — a sort of metrosexual president, and then Joe Biden who in some ways is an older version of masculinity, but was always an openly emotional kind of person," Alberti says.
Alberti doubts President-elect Trump will form a similar bond with Vice President-elect Mike Pence because both exhibit more dominant forms of male masculinity. But he adds that Trump may be at the start of a bromance with someone else: Russian President Vladimir Putin.
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(Answers have been edited for clarity and brevity.)