BRUSSELS—What the last few days of Trumpian summitry have established beyond a reasonable doubt is the U.S. president’s inclination to confuse photo-ops (including what look like family photos) with policy. The most recent example was the chaotic minuet at the DMZ with North Korea’s tyrant Kim Jong Un, which has rewarded Kim with the prestige of a presidential visit without demanding he first get rid of his nukes.

That was preceded at the Osaka G-20 by backslapping bonhomie with Saudi Arabia’s crown prince, accused by U.S. intelligence of ordering a journalist’s butchering, and a few yucks with Russian President Vladimir Putin about his meddling in U.S. elections and the need to get rid of reporters. Not really all that funny when you think more than 20 journalists have died violently since Putin’s been in power.

Kim, Putin, Mohammed bin Salman, Xi Jinping, and Donald J. Trump all smiled for the cameras like salesmen pushing timeshares and telling you to trust them.

But here’s the problem, and a growing one, for America’s traditional allies. How is it possible to trust the current president of the United States, when he aligns himself so comfortably with these authoritarian characters, aping their anti-democratic world view for the cameras?

The dilemma presented itself in bold relief at a conference over the weekend in Brussels, home to the European Union and NATO headquarters. The German Marshall Fund’s Brussels Forum, an annual gathering meant to cement transatlantic relations, more recently has been devoted to lamenting the Trump presidency—and looking for ways to survive it.

U.S. officials here find themselves in an almost impossible position, trying to reassure allies that Trump doesn’t really mean his tweets, and that there’s some kind of grand strategy in his mad rush to embrace monstrous authoritarians around the world. But that’s wearing thin, and the spectacle can be worse than disconcerting.

“ If Russia invades Latvia, that's not the only place they're going. They have a plan, and it's going to go far beyond that. ” — U.S. Ambassador to NATO Kay Bailey Hutchison

I asked NATO’s Supreme Allied Commander in Europe, U.S. Air Force Gen. Tod Wolters, if his troops would defend NATO member Latvia from Moscow. The obvious answer, the necessary answer, by treaty and by common sense, should be a straightforward yes. But Wolters danced around it as if second-guessing his commander-in-chief.

“All you have to do is go back and take a look at what unfolded in 9/11 with respect to the attack on the homeland of the United States, and look at the response that occurred on behalf of NATO,” he said. “Those are obviously the comforts, if you will, of the world's greatest alliance.”

That wasn’t direct enough for the U.S. ambassador to NATO, Kay Bailey Hutchison, who, unprompted, offered more direct assurances.

“If Latvia is invaded by Russia, we will be there. There is no doubt about it,” she told the audience. “If Russia invades Latvia, that's not the only place they're going. They have a plan, and it's going to go far beyond that, and we are going to stop it before it spreads.”

She added that the U.S. still had a chance to negotiate a healthier relationship with Beijing, but Moscow? Not so much.

“ What we see in Washington, D.C., and hear here, it doesn’t fit together. ” — Senior European diplomat in Brussels

“I don't think we have a chance with Russia,” she said, a statement that seemed at odds with the chummy Trump-Putin meeting that unfolded just a day later in Japan.

“It’s highly disturbing,” said one senior diplomat Saturday, sympathetic toward Hutchison’s awkward position. “What we see in Washington, D.C., and hear here, it doesn’t fit together. The NATO ambassador has to… try to calm things down,” something she apparently has to do regularly.

“‘Actions, not words’ has been their talking point for a year and a half,” a senior European official griped to me. She said European trust in the “this too shall pass” defense “is eroding.”

Multiple European officials spoke sotto voce about their exhaustion trying 24/7 to decipher the significance of the latest midnight presidential tantrum in screaming capital letters that seems to upend agreed upon Syria policy, or China trade policy, or Iran policy that their local U.S. ambassador or general had tried to rationalize.

Trump has played bad-cop-good-cop rolled into one crazy cop, showing fangs one minute, fawning the next, so often that his own team doesn’t really know what to believe. Is he pulling troops out of Syria? Sanctioning half of China’s trade? Obliterating Iran? European officials have gone bleary-eyed from the constant tea-leaf tweet-reading they and their American counterparts rely on to figure out which way the hot air is blowing out of the Oval Office.

“ By making light of Russia's interference in our democracy, the president is undermining efforts to deter Russia's attacks. ” — Laura Rosenberger, German Marshall Fund’s Alliance for Securing Democracy

“Top advisers say one thing, the president says another thing. There are reverses of course by the president on a daily basis,” said European Parliament Member Marietje Schaake, from the Netherlands, empowered to speak more freely as she wraps up her final week after a decade in government. “There are a lot of strong words but there is also a lot of flip-flopping…. I worry that the credibility of the United States is declining very rapidly in Europe.”

Another senior European official called Trump’s smirking "don't meddle in the election” moment with Putin “absolutely cynical,” and an insult to his closest allies, some of whom are under constant cyber attacks and propaganda assaults from Moscow’s security services.

“By making light of Russia's interference in our democracy, the president is undermining efforts to deter Russia's attacks—including the executive order that Trump himself signed last fall warning of consequences for such activities,” added Laura Rosenberger, a former Obama administration official, and a director of the German Marshall Fund’s Alliance for Securing Democracy program. Her team released a report on countering authoritarian interference just a day or so before the Trump-Putin laugh-in.

And as much as the Europeans decry Trump’s Putin/dictator fixation, and his mercurial decision-making style, they are just plain confused by his rejection of using alliances to pressure adversaries.

“ For all the griping you say you hear, I hear an equal amount of ‘he’s great, he finally makes things happen.’ ”

“What we don’t understand is why Trump isn’t making an effort to build a global coalition on China,” a senior European diplomat said. “We have some of the same issues with Huawei, but when we reach out to work together, we get pushed back,” he said.

Trump’s G-20 turnaround on the Chinese company that Trump’s national security team had portrayed as an international pariah left the senior European official gut-punched, wondering what he’s going to tell other officials and companies at home, as he had been fighting to get his country to step away from Huawei’s 5G.

“It will be very hard for Europeans to be convinced... to have the utmost concern about Huawei if we’ve just heard that Americans are selling their technology to the same company,” agreed parliament member Schaake.

When you combine that dynamic with Trump’s threats to sanction E.U. companies doing the same thing, the overall conclusion is, the enemy of the enemy is my friend, the senior European diplomat said. “We get pushed closer to China,” or at the very least, European companies do.

And if Trump changed his mind on one-half of the U.S. ban on Huawei this week, what’s to say he won’t drop it all next week in order to do a China trade deal? The European politician just shook his head.

“He’s very direct, there’s no ambiguity,” Trump’s representative of the European Union explained to me in a sitdown a couple weeks earlier at a gathering of Central European leaders in Bratislava–though I was not able to reach him for reaction to the G20.

“For all the griping you say you hear, I hear an equal amount of ‘he’s great, he finally makes things happen,’” Sundland said. “We are like an old married couple. We’re never getting divorced, but we have some issues to hash out.”

“Our bluntness about them does not change our unshakable alliance,” he said.

But one of the senior European officials countered with the dire prediction of German scholar Constanze Stelzenmüller of Brookings Institute, who warned at an Intelligence Squared debate at the conference that Trump’s attacks on his allies and the press, and the coddling of dictators like Putin were leading to a “silent spring” that is shredding international relations.

“We can last another year or so,” the senior European official said. But if Trump is elected again, “Europe will no longer see the United States as the shining bastion of democracy, human rights and freedom.” They won’t try to emulate Americans, or rely on them.