But Trump said as much, by implication, in his remarks at the unveiling of an Article 5 memorial at NATO's Brussels headquarters.
Viewing the paintings, Mrs. Trump chatted with Brigitte Macron, whose husband won the French presidency this month.
The Wall Street Journal editorial board pushed back on Thursday, lambasting the press for crying wolf every time Trump opens his mouth. Trump has remained extremely sensitive to assumptions that Russia's actions handed him the White House.
But as President he has walked at least 90% of that back-by supporting Montenegro's entry into the alliance despite Russia's furious opposition; by following through with new North Atlantic Treaty Organisation deployments on the alliance's eastern front, including a US -led battalion; and this week with a new North Atlantic Treaty Organisation commitment to join the coalition against Islamic State.
Cajoled on issues like climate change and NATO's defense pact, he's responded by scolding some of the United States' most loyal allies for not paying their fair share.
The drumbeat of revelations surrounding his campaign's alleged ties to Moscow has only grown louder as Trump crisscrossed Europe and the Middle East, weighing on his discussions with European leaders, who, deeply skeptical of Trump's intentions, have found little solace during their interactions with the new USA president.
Trump waxed lyrical about his first foreign trip, which has offered distraction to ethics questions at home, notably over alleged campaign ties to Russian Federation.
Although he has since softened his tone in phone calls and meetings with Western leaders, Trump's sharp words on Thursday recalled his awkward meeting with Angela Merkel in March, when he pressed the German chancellor for Germany to meet NATO's military spending target.
Donald Trump proved once again that diplomacy is not his strong suit after he told European leaders that Germans are "very bad".
Trump's comments will disappoint alliance leaders who had hoped for a public commitment from the USA president to NATO's security guarantees, which he called into question during his presidential campaign past year.
"I think the President is looking at it", Cohn said.
The day will feature a welcoming ceremony and concert at the remains of an ancient Greek temple, as well as a relentless number of meetings, many of which White House aides are hoping to keep short in order to keep Trump's attention. The omission was stark, given Trump's wavering on the commitment during the campaign trail and his otherwise sharp focus on other countries boosting their defense expenditures.
Anne Applebaum, a visiting professor at the LSE Institute of Global Affairs, tweeted that it was "very striking that Trump made a point of "not lecturing" the Saudis, and then arrived in Brussels and lectured Europeans". Speaking to reporters aboard Air Force One on Thursday, Trump's chief economic adviser Gary Cohn said Trump had yet to formulate a plan.
"With continued engagement by both sides, and with the political will to prioritize long-term gains for our economies and our broader relationship, the United States and the European Union could achieve what we set out to do in 2013: conclude an ambitious, balanced, comprehensive, and high-standard agreement that strengthens the transatlantic partnership and builds upon our economic relationship in ways that raise living standards and increase competitiveness on both sides of the Atlantic", the report read. European leaders went out of their way to try to accommodate Trump and his, shall we say, unique qualities, but he managed to alienate many of America's closest allies anyway.
Trade will also be a big topic, with Cohn saying the United States' guiding principle will be "we will treat you the way you treat us", suggesting that retaliatory tariffs could be imposed.