Washington (CNN) Next week marks the anniversaries of twin American tours de force that liberated and rebuilt Europe, enshrining an unprecedented era of peace and freedom.

So it's ironic and disturbing to proponents of the transatlantic alliance that remembrances of the D-Day landings and the Marshall Plan should coincide with the most fraught period in Europe-US relations in decades.

The situation darkened further on Wednesday following indications that President Donald Trump will pull out of the Paris climate agreement , even as the shock waves of his jarring trip to the continent last week still reverberated.

The decision will exacerbate a widespread feeling in Europe that the United States, after so long as a force for stability in the Western world, is now a source of disequilibrium and disruption and is set on a political course that will ultimately damage the transatlantic alliance. And that the "America First" approach is a retreat into isolationism -- and a rejection of multilateral efforts to solving global problems.

Bush comparisons

Many observers have commented that the relationship between the United States and Europe is now at its lowest point since the estrangement over the US push to war in Iraq in 2003, which opened deep divisions.

Back then, the United States had stated that it would not implement a major global climate accord -- the Kyoto Protocol.

The Bush administration's hostility to the International Criminal Court meanwhile called into question its commitment to the principles of multilateralism.

But the parallel may actually underestimate the discord that currently exists across the Atlantic as the remaining veterans of the Normandy landings mark the 73rd anniversary of D-Day on June 6 and foreign policy elites remember the June 5, 1947, speech at Harvard University by George C. Marshall that inaugurated the post-war European aid plan that is seen as one of the triumphs of American foreign policy.

There's another difference from 2003 as well. Back then, there was no suggestion that the bedrock principles of the European-US alliance were at stake or would be undermined by the administration of President George W. Bush.

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NATO questions

Now, there are serious questions in Europe whether Trump is committed to the US security guarantees that underpin NATO.

"This time, it is about the fundamentals of European security which Iraq was not about," said Jan Techau of the American Academy in Berlin, adding that Trump had created a great sense of "nervousness and uncertainty" in Europe.

"He missed a huge opportunity in Brussels to take some of this nervousness out of the market," Techau said.

Heather Conley, who served in the Bush administration as deputy assistant secretary of state for Europe and Eurasian Affairs, noted the tensions were acute in 2003, but said the divisions are even more fundamental now.

"There wasn't a sense that the US was really removing itself from the international system. In some ways, there is a more broad scale rejection of multilateralism," said Conley, now with the Center for Strategic and International Studies.

There's also a feeling across the Atlantic that not only does Trump have little conception of the historical ties that have bound the transatlantic alliance together, including years of solidarity in the Cold War period, but that his impulses and positions on issues like race, Islam and the use of military force fundamentally jar with European values.

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Trump and strongmen

His apparent political kinship, for example, with strongman leaders like those from Saudi Arabia, Turkey and Russia has raised questions whether the President of the United States is now really a custodian of Western values, including press freedom and support for democracy and human rights around the world.

While the disconnect between the Bush administration and some top European powers was bruising, opposition to the Iraq War was not universal: Germany and France at the time were vehemently against the invasion but other governments, in Britain and Spain for instance backed it.

But when it comes to support for the Paris climate deal, Britain, France, Germany and Italy reaffirmed support for the Paris deal when their leaders met Trump at the G-7 summit last week.

Alongside German Chancellor Angela Merkel, the other key player in framing Europe's response to Trump will be new French President Emmanuel Macron.

His philosophy appears in many ways to be a repudiation of the populist rhetoric that helped Trump win the White House. And after meeting Trump for the first time in Brussels last week, he suggested their long, white-knuckled handshake before the cameras was a moment of truth.

"We have to show that we won't make concessions, even symbolic ones," Macron told a French newspaper, before comparing Trump's leadership style to that of two autocrats, Russian President Vladimir Putin and Turkish President Recep Tayyip Erdogan.

Such public questioning of the values that undergird the current American presidency is another reason why the tensions between the US and Europe in 2017 and 2003 are not exact.

Recriminations have deepened since Trump left Europe following his contentious visits to the NATO summit and the G-7 meetings last week. Merkel warned at the weekend that the days when Europe could totally rely on its allies -- namely the US -- were perhaps in the past.

Apparently stung by her comments, Trump aimed a lacerating tweet towards Berlin on Tuesday.

We have a MASSIVE trade deficit with Germany, plus they pay FAR LESS than they should on NATO & military. Very bad for U.S. This will change — Donald J. Trump (@realDonaldTrump) May 30, 2017

"We have a MASSIVE trade deficit with Germany, plus they pay FAR LESS than they should on NATO & military. Very bad for U.S. This will change," Trump wrote.

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Populist rhetoric

Trump's populist rhetoric on trade has meanwhile has convinced many Europeans that a proposed Transatlantic Trade and Investment Partnership is effectively dead.

The spectacle of the US president and the German chancellor -- the leader of the most powerful European nation -- so publicly at odds is a rare one, though not unprecedented. The atmosphere between Bush and German Chancellor Gerhard Schroeder, for example, was extremely tense during the Iraq War period.

But the niggling between Merkel and Trump is becoming especially intense and increasingly political, with both apparently at least for now perceiving a domestic advantage in waging the tussle.

Merkel is facing a re-election race in September, and has to contend with Trump's deep unpopularity in Germany as well as attempts by her rivals to use her efforts to engage the mercurial US president to expose her electorally.

The US President meanwhile treated his trip to Brussels almost as an election rally -- berating European leaders for what he sees as their freeloading off of US taxpayers, and the failure of some European states to live up to promises to spend at least 2 % of the GDP on defense.

While he trampled all over European sensitivities, Trump's blast added up to a campaign promise honored among his supporters: His vows to make US allies pay more for their defense were a centerpiece of his stump speech last year.

Trump is likely to receive a similar payoff from supporters for dumping the Paris climate deal -- one reason why his White House may not care much about what will be a stiff European rebuke when he formally announces the move.

The administration, meanwhile, is simply ridiculing the idea of tensions across the Atlantic.

White House spokesman Sean Spicer said Tuesday that Trump's relations with Merkel, despite the awkward atmospherics of her White House visit earlier this year and her comments at the weekend, were "fairly unbelievable."

And in a Wall Street Journal op-ed on Wednesday, Trump's national security adviser H.R. McMaster and top economic adviser Gary Cohn insisted that Trump's trip had "deepened our relationships" in Europe by asking for more buy-in from allies.

The White House has also insisted that despite Trump not talking about Article 5 at an event in Brussels marking the only time the clause has been invoked, after the US was attacked by al Qaeda on 9/11, there was no question that US support for NATO was ebbing.

The fact that there are such differing perceptions of the same event on either side of the Atlantic is an eloquent metaphor for the current state of the alliance itself.