"The fundamental question of our time is whether the West has the will to survive," Trump said in Warsaw, Poland, citing his host nation's long battles against tyranny as an example of the tenacity needed to preserve Western values.
On the surface, Trump's speech was exactly the kind of message Europe's leaders have pined to hear. He reaffirmed NATO's Article 5 principle of mutual defense, albeit with a swipe at member countries over defense spending. He rapped Russia for "destabilizing activities in Ukraine and elsewhere."
After hammering Western institutions during his campaign, the US President, sticking unusually to a script, offered a moving anthem to the West's cultural, scientific and economic contributions to the world.
"We write symphonies. We pursue innovation. We celebrate our ancient heroes, embrace our timeless traditions and customs, and always seek to explore and discover brand-new frontiers ... We treasure the rule of law and protect the right to free speech and free expression," Trump said.
Yet embedded in his speech, and evident in the President's sometimes unchained behavior in his first day in Europe, were hints and illustrations of just why he has proven so shocking to Europeans and so vexing to their leaders since taking office.
On a continent where Russia's territorial maneuvering is feared, he yet again refused to accept allegations that Moscow was solely responsible for interference in the US election.
And standing on soil once controlled by the Soviet Union, the President threw his own intelligence agencies under the bus, arguing their failure to correctly assess Iraq's weapons of mass destruction programs devalued their assessments on Russia's efforts to influence the democratic process.
It would be difficult to think of a way that Trump could better please Russian President Vladimir Putin, ahead of their first formal meeting in Germany on Friday.
Trump's performance hinted at a huge irony in his relations with Europe. He was presenting himself as the guarantor of the West's freedoms and values, but by their actions and words, some key European leaders have shown they regard Trump himself as the biggest threat to those traditions.
In Poland, a nation criticized elsewhere in Europe for eroding press freedom, Trump launched a new tirade against American journalism, including that of CNN and NBC, branding it "fake news" and asked his host, Polish leader Andrzej Duda, "Do you have that also, by the way, Mr. President?"
Future conflicts with European leaders
Trump's overall pro-Western tone, however, contained the kernels of future clashes with Europe. His vision of the West was closer to his creed of strong immigration laws, uncompromising opposition to Islamic radicalism and pared-back government that his own supporters crave, unlike the more traditional version of Western liberalism prized in Europe.
"Do we have the confidence in our values to defend them at any cost? Do we have enough respect for our citizens to protect our borders?" Trump said in his speech. "Do we have the desire and the courage to preserve our civilization in the face of those who would subvert and destroy it?"
The President was talking about "radical Islamic terrorism," which he equated to oppressive ideologies like communism and Nazism that posed an existential threat to Western civilization.
"America and Europe have suffered one terror attack after another. We're going to get it to stop," he said.
Though many European leaders would quarrel with Trump's view that terrorism poses an existential threat to Western life, they don't dispute it is a threat and there is a growing desire to tighten the outer borders of the European Union.
Yet Trump's methods for waging this fight, including travel bans, bans on refugee entries and strong border enforcement are considered by many Europeans as anathema to the fundamental values of the West itself.
Trump also made comments that appeared to recount the secularism that is far more prevalent in European politics than it is in America.
"The people of Poland, the people of America, and the people of Europe still cry out 'We want God,'" Trump said, in a message that may play better in largely Catholic Poland than elsewhere.
The clear threat that is seen by many Europeans is climate change -- and Trump has already deeply soured his relations with the continent, possibly irrevocably, by pulling out of the Paris accord -- didn't merit a word in his speech.
And the President seemed to take aim at the European Union, and its form of government itself, when, suggesting that there was a swamp that needed to be drained in Brussels too.
"This danger is invisible to some but familiar to the Poles: the steady creep of government bureaucracy that drains the vitality and wealth of the people," he said. "The West became great not because of paperwork and regulations but because people were allowed to chase their dreams and pursue their destinies."
The concept of government itself however, despite widespread frustration at EU red tape, does not suffer the toxic reputation in Europe as it does in the US. Welfare states and state-run services win wide pubic support in Europe.
Message to Merkel and Macron?
It will irritate some leaders, German Chancellor Angela Merkel especially perhaps, that Trump chose to spell out his message in Poland, which has chafed against German power in the EU and where the right-wing government has been accused of eroding some basic bloc freedoms.
Given his deep unpopularity in Europe -- a recent Pew Global Attitudes Poll showed that only 11% of Germans, 14% of French and 7% of Spaniards had confidence in Trump to do the right thing regarding world affairs -- there were few places he could have gone in the continent to give a speech.
As it was, supporters of President Andrzej Duda were offered free bus rides to give him a warm reception.
The content of his message also laid down the gauntlet to leaders like Merkel and new French President Emmanuel Macron, who are the political drivers of Europe and are seeking to reinvigorate the bloc after some tough years.
Merkel, who met Trump for talks in Hamburg on Thursday night, has sharply rebuked Trump's positions on foreign policy, trade and climate, saying as recently as last week that "whoever believes the problems of this world can be solved by isolationism and protectionism is making a tremendous error."
Ambassador Nicholas Burns, who played key foreign policy roles for both Democratic and Republican presidents, said Trump had adopted an unhelpful role in his positioning on the West.
"He is almost appearing as the critic of the West, of its major institutions, NATO and the EU, rather than as a uniter," Burns told CNN. "It played well with this crowd in Poland, it is not going to play well with Emmanuel Macron, Angela Merkel and all those leaders at the G20 summit who want a more pluralistic and want a more unified vision, an optimistic vision of the West."
"He has given up that leadership role that most American presidents have played," he added.
There used to be a saying that politics stopped at the water's edge when a president went overseas on behalf of the nation.
For sure, that tradition has frayed over the years, but Trump well and truly obliterated it, with his attacks on the media, attitude to Russian election interference claims and attack on his predecessor Barack Obama, whom he said had done nothing to protect last year's election -- a statement not rooted in fact.
As always, Trump's supporters will see his belligerent behavior as exactly the performance they were signing up for when they sent him to the White House last November.
But for nervous US allies, who are beginning to look past the United States for leadership and partnership, this dose of classic Trump will likely have exacerbated their concerns on the eve of the G20 summit. And it will do little to fuse differing visions between Washington and Europe about the ultimate destiny of the West.