David A. Andelman, member of the board of contributors of USA Today, is the author of "A Shattered Peace: Versailles 1919 and the Price We Pay Today." He formerly was a foreign correspondent for The New York Times and CBS News. Follow him on Twitter @DavidAndelman .

(CNN) President Donald Trump has taken a wrecking ball to generations of carefully constructed American friendships and alliances while quietly providing new aid and comfort to Vladimir Putin's Russia during his brief flight of fancy across Europe.

Already, his bags barely unpacked from his overseas trip, across Europe, a host of new declarations and scenarios are playing out that will do little good for the United States and its most profound interests.

On Sunday, German Chancellor Angela Merkel, who'd sat tight-lipped last week as Trump trashed a whole list of priorities that she and her European counterparts hold so dear, quickly struck back. Europe, she said, can no longer count on the United States under Trump and must "really take our fate into our own hands.

"The times in which we could rely fully on others -- they are somewhat over," Merkel told a campaign rally in Munich. "This is what I experienced in the last few days." And she's not the only one sharing such a perspective among the G7 industrial countries and the entire European Union, all of whom had a firsthand dose of Trump hubris.

France's new President, Emmanuel Macron, explained his hand-wrestling encounter with Trump at the European summit to Journal du Dimanche. Macron wanted to get across that he would not be giving in on issues large or small. "It's not the alpha and the omega of politics, but a moment of truth," he told France's leading Sunday newspaper.

Indeed, on Monday, barely two days after Trump returned home, Macron was already welcoming Putin to Versailles, the Russian leader apparently quite eager to strengthen economic ties with a Western Europe that recognizes it may need to chart new territory on its own.

While the depths of this damage may not be immediately apparent, it is no less profound.

Since the United States launched the Marshall Plan in 1948, picking up Europe after World War II, both sides of the Atlantic have cared deeply about the welfare of the other without holding either hostage.

And indeed, the White House succeeded in minimizing some negative reporting this time by keeping the President carefully quarantined from the press at every stop. Moreover, Trump himself, at least in most of his public appearances, stuck largely to carefully telepromptered messages, though neutering even his more generous remarks by some of his off-prompter gestures.

Perhaps no single image was as powerful as the much-played shot of an arrogant and aggressive Trump shoving aside Dusko Markovic , the white-haired, socialist Prime Minister of Montenegro, celebrating his nation's first trip to a NATO summit. For 11 years, the tiny former Yugoslav democracy has sought membership in NATO -- and this was the welcoming gesture from the alliance's most powerful member.

JUST WATCHED Did Trump push Montenegro leader aside? Replay More Videos ... MUST WATCH Did Trump push Montenegro leader aside? 00:53

The Montenegrin later graciously dismissed the action : "This was an inoffensive situation," Markovic said, "it is natural for the President of the United States to be in the first row."

Indeed, Montenegro's presence as NATO's 29th member, would appear to illustrate the point Trump was trying to make in his formal address to the heads of the alliance's members. The impoverished Balkan state commits barely 1.3% of its gross domestic product to its military budget -- a far cry from the 2% or more that Trump is demanding be coughed up by each nation, and which sounded to many like a protection racket.

You can count on our upholding our agreement under the alliance's Article 5 that an attack on one is an attack on all, only if you pay up, Trump was effectively saying.

Actually, the last and indeed only time that Article 5 has been formally invoked was after 9/11 when the alliance came to the aid of the United States and joined American forces in a military incursion in Afghanistan where it still maintains a presence years and hundreds of NATO member casualties later.

But this equally illustrates the central message that Trump utterly failed to appreciate in reiterating his 2% argument. There is more than one way to be a friend, or an ally. For the formal induction of Montenegro into NATO's ranks at a June 5 ceremony will mean the alliance now controls the entire strategic Adriatic coast of the Mediterranean, where Russia is struggling to maintain a final toehold from its sprawling air and naval facility in Bashar al-Assad's Syria.

Trump appears to have grasped none of these subtleties, his week going steadily downhill as he worked his way from a friendly reception in the Middle East to a borderline disaster in Western Europe.

While Trump may have trotted out massive arms deals with the Saudis, apparently lost on his speechwriters and political choreographers was the reality that many of these arms deals -- totaling more than $350 billion over 10 years -- were actually negotiated under his predecessor.

Moreover, only a handful were any more than vague promises from a kingdom that has lately gone from Croesan riches to worries about its ability to make good on vast commitments even to its own people as oil has plummeted below $50 a barrel

What Trump failed to realize is that Western Europe is a far older, deeper-pocketed and reliable consumer of American weaponry and munitions than Sunni nations over whom we have little or no control the moment the ink is dried on these cut-rate contracts.

Moreover, with a federal appeals court ramming another stake through the heart of the President's immigration proposal, he also failed to appreciate that these same European allies he was taking to the fiscal woodshed may turn out to be our last line of defense against the terrorists posing as refugees who are apparently Trump's biggest boogeyman.

Indeed, the German press went wild when, with Merkel sitting mutely, her lips pursed, Trump took off in Brussels against Germany. "The Germans are bad, very bad," leading German newsweekly Der Spiegel quoted him as saying behind closed doors.

Trump counselor Gary Cohn tried to clarify that "he said they're very bad on trade, but he doesn't have a problem with Germany. He said his dad is from Germany." Which only illustrates a further point, as Der Spiegel went on to quote Trump as saying, "See the millions of cars they are selling to the US. Terrible. We will stop this."

Two problems: First, many of these German cars are actually produced in these companies' US manufacturing facilities that employ tens of thousands of American workers. But of greater importance is the reality that Germany and its trading system are part of the EU with a common tariff and economic policy. If Trump tries to tear up that trade pact with the EU and start over, there will be a cataclysmic economic collapse on both sides of the Atlantic.

Follow CNN Opinion Join us on Twitter and Facebook

And in the final slap at America's allies and friends, Trump was the only G7 leader not to sign a reaffirmation of the Paris climate accords. "I will make my final decision on the Paris Accord next week!" he tweeted archly before heading off for a final "America First" speech to US military forces assembled at the NATO base at Sigonella, then boarding Air Force One.