Had French President Emmanuel Macron been paying close attention, he would have recognized quickly just how fraught his coming exchange with Donald Trump was to be.
The two leaders had met briefly earlier that day, exchanging a firm, prolonged, "not innocent" handshake that drew attention for its unbound intensity. Now, hours later, as Macron approached Trump and other world leaders at the opening of NATO's new headquarters in Brussels last week, the U.S. president offered several non-verbal cues indicating his desire to re-establish the global pecking order.
The first came well before he and Macron were face-to-face. Walking toward each other, Trumpreached out to King Philippe of Belgium, who stood directly to his right, to offer an impromptu handshake. The King seemed caught off-guard. For good reason. No one in their group was making any such gesture.
Trump's offer seemed out of place. But Florin Dolcos, a University of Illinois associate psychology professor and faculty member at the Beckman Institute's Cognitive Neuroscience Group, suggested it was a deliberate. And the intended audience wasn't Philippe but Macron.
"That's a signal Trump was sending: 'This is where you should come first because I'm the alpha here,'" Dolcos said. "'Iinitiated with the other guy.'"
Moments later, another cue. With the two still walking towards each other, Trump looked up at Macron and opened his arms ― a signal typically reserved for family and friends, not two world leaders who'd just met. Once again, Dolcos suspected Trump was making a nonverbal signal to his French counterpart.
"I think it is a learned behavior. Because typically you don't do that. You do it with people very close to you in natural circumstances. Not people you don't really know," he said. "In a way it could be seen as a trap."
Macron didn't fall for it. Instead, he greeted a few others before making his way to Trump. When he did finally arrive, Trump pounced, taking Macron's hand and pulling it violently away from his body with enough force to turn Macron roughly 50 degrees.
Dolcos again saw a tactical play. Unable to torque his arm, Macron was rendered powerless. He attempted to pull away and Trump refused to let him go.
Macron put his other hand on Trump to pry himself loose. And when he finally freed himself, Trump gave him a pat on the shoulder, ending the exchange squarely on his terms.
Another bizarre, dramatic, uncomfortable handshake with a world leader was in the books, bouncing its way across the Internet to the wonderment of all.
"It goes down to asserting dominance," said Dolcos. "Why he wants to do that? I don't know. It looks, to me, like he is trying too hard.... It looks ridiculous"
If you want to better understand Donald Trump ― his presidency, his approach personal diplomacy, even his psyche ― simply follow his hands.
Those hands, and their unexceptional digits, have been the source of immense insecurity, prompting him to lash out at critics and boast about his genitalia. They give insights into his marriage for the way they search ― ever so subtly and often unsuccessfully ― for his wife's embrace. They tell us about his comfort in office as he attempts to find his footing on the world stage. And they illustrate his preoccupation with imagery and the role it plays in advancing his agenda.
"I just think the president is very cognizant of the optics of what it looks like at these multilateral meetings with world leaders," said Sam Nunberg, a former Trump aide, "and I even think [the handshake] is symbolic to the America First theme of his presidency and campaign."
The Trump handshake has become most unique greeting in all of politics. Before he nearly tore off Emmanuel Macron's arm, Trump crushed the fingers of Japanese Prime Minister Shinzo Abe.
When he unveiled his Supreme Court nominee Neil Gorsuch during a East Wing ceremony, he followed suit by yanking the Justice's entire body three times in his direction.
Trump memorably refused to shake hands with German Chancellor Angela Merkel when she visited him in a testy Oval Office exchange.