During his inaugural international trip as the leader of the free world, President Donald Trump learned the problem with first impressions—you only get to make one.

After indulging the royals of Saudi Arabia with assurances that he was “not here to lecture”—in exchange for gold chains and glowing orbs—Trump took a much harder stance toward major Western democracies, distancing his administration politically and, in some cases, personally from some of America’s oldest and closest allies. The concept of diplomacy as a pursuit of mutually beneficial terms for both parties stood in stark relief against Trump’s worldview, which divvies up the world into two groups: winners and losers.

In a meeting with European Union leaders on Wednesday, Trump reportedly dubbed the Germans “bad, very bad” and decried current U.S. military commitments to Europe as “unfair to the people and taxpayers of the United States.” During a ceremony at NATO headquarters in Brussels meant to dedicate a memorial to the alliance’s strength in the wake of the 9/11 terrorist attacks, Trump scolded NATO member nations for “not paying what they should be paying.”

Rather than speak to leaders from the 28 nations of which NATO is comprised, Trump instead, it appeared, spoke to his base. Trump declined to recommit the United States to upholding Article 5 of the NATO Treaty, which stipulates that an attack against one member nation is considered an attack against all. The omission—later downplayed by White House press secretary Sean Spicer—underscores threats Trump made as a candidate to treat Article 5 as conditional, based on whether a country was spending enough on defense.

The only form of offensive action Trump seemed to endorse during the event, it seemed, was shoving the prime minister of Montenegro.

(Dusko Markovic, the leader of the small Balkan nation in question, later downplayed the shove as “inoffensive.”)

Even handshakes with allied leaders became confrontational. After a white-knuckle grin-and-grip between Trump and President Emmanuel Macron of France, the newly elected French leader suggested that the salutation “was not innocent.”

Trump’s insistence upon returning stateside that the “trip was a great success for America,” therefore, came as a surprise to European allies who viewed the trip through a much darker lens. Citing Trump’s silence on threats of Russian aggression in the region, his disinterest in committing to deterrence efforts, and his six-against-one stance athwart the enactment of the Paris Agreement, Western leaders left the NATO and G7 talks resigned to the assumption that the era of America intervening on its allies’ behalf is over.

German Chancellor Angela Merkel, recovering from the geopolitical whiplash of meeting with both Barack Obama and Trump in the span of three days, told a Bavarian crowd on Sunday that Europe’s ability to rely on outside protection was “over, to a certain extent. This is what I have experienced in the last few days.” With U.S. leadership signalling an end to the decades-long status quo, Merkel continued, Europe “really must take our fate into our own hands.”

Macron dismissed Trump’s antics as the “diplomacy of public invective,” which could be combated only by strong-armed—or, rather, strong-handed—bilateral talks. Likening Trump to strongmen like Russian President Vladimir Putin and Turkish President Recep Erdoğan, Macron promised a challenge to Trump in future negotiations: “In my bilateral dialogues, I don’t let anything pass—that is how we are respected.”

While the president of France implied that Trump’s bluster could be mitigated by a more muscular approach to bilateral relations, however, U.S. diplomats saw arrogance that could seriously hinder American diplomacy.

“When it comes to diplomacy, President Trump is a drunk tourist,” a State Department official told the Daily Beast. “Loud and tacky, shoving his way around the dance floor. He steps on others without realizing it. It’s ineffectual.”

But far more concerning, the official said, was Trump’s “arrogance” in threatening to single-handedly thwart the Paris Agreement, which obliges member states to slash carbon emissions to combat global climate change. Trump’s reality-show declaration that he’ll make a final decision on his commitment to the accord “next week!” is, in the official’s terms, “an abdication of American leadership.”

“One hundred and ninety-five nations never agree on anything, so when they do, accepting the measure should be easy,” the official said. “The United States needs to be out front on this pact.”

Trump’s explicit skepticism of multinational diplomacy comes at a time when internal tensions within allied nations make stepping back from Europe particularly risky. As recent elections in France, Austria, and the United Kingdom have demonstrated rather dramatically, the European Union’s nationalist-vs.-globalist battles are threatening the world’s largest economic and political union from within.

Meanwhile, an increasingly bellicose Russia—whose post-Cold War ambitions of European expansionism have heretofore largely been contained by NATO—needs little more excuse than a crack in the facade of NATO’s collective defense agreement to encourage more aggression in the vein of past actions in Crimea and South Ossetia.

On both sides of the Atlantic, however, hope continues to spring that the realities of international diplomacy will settle in.

“Still,” the State Department official said, “we continue to hope for the best.”