He did not bow to the king. Not right away, at least.
Obama's bent-waist handshake with King Abdullah caused one of the great furors of his first year as president.
But then, later that day: was that a …?
A bow? Surely not, some insisted, after watching Trump bend his knees, slump forward and bob his head to let King Salman place the honorary collar of Saudi Arabia's founder around his neck.
The White House did not immediately respond when asked if Trump had softened his position on bowing, after criticizing Obama about it on more than one occasion.
Whatever he was doing with the king, Trump appears to have left his Washington troubles only to walk into the same quagmire of diplomatic body language as so many presidents past.
It's not clear why, exactly, Obama's gesture to the king — “It wasn't a bow. He grasped his hand with two hands, and he's taller,” an anonymous aide insisted to Politico in 2009. — caused him so much trouble.
President George H.W. Bush had done the same thing to a dead Japanese emperor, as the New York Times noted. And the second President Bush diplomatically kissed and held hands with Saudi royalty.
When it was followed by a deep bow to the Japanese emperor, Obama endured years of mockery in which his every head tilt risked being called prostration, with sneering headlines catalogued by the Atlantic: Obama bows to the mayor of Tampa; Obama bows to a robot.
“American presidents do not bow before foreign dignitaries, whether they are princes, kings, or emperors,” the Weekly Standard chided.
Trump sure wouldn't, at least, as he made clear on Twitter several times before his presidential campaign.
Many observers could not resist a superficial comparison to the past when he began his foreign tour.
“Trump shakes hands with Saudi leader, doesn't bow as Obama appeared to do,” as Fox News put it.
“How Trump just greeted Saudi Arabia’s king is remarkably different than how Obama did in 2009,” the Blaze remarked, noting that Trump shook the king's hand (though Obama has done that too) and his wife did not wear a hijab (neither did Michelle Obama.)
But on the homepage of the Arab daily Asharq al-Awsat, and the snarky feeds of many Trump critics, focused on a different picture.
And while some insisted Trump's little dip could not compare to his predecessor's manifold acts of humility, one of the president's top political backers made no excuses:
In fact, Trump bowed no more or less than other presidents who have worn the collar of Abdulaziz al-Saud, which the kingdom bestows as an honor on foreign dignitaries.
Trump did it. Obama did it. Bush did it.
There was no sign any of this was clouding Trump's trip. On the same morning of his upright handshake and maybe-bow, he took part in another long tradition of American officials on trips abroad: