In an apparent effort to tone down his inflammatory rhetoric and appear presidential, Donald Trump refrained from repeating the controversial proposal that had originally catapulted him in the media spotlight and made him a darling of right-wing zealots in the US and abroad.

His promise to build a wall along the border with Mexico did not feature at all in what was billed as the Republican frontrunner's major foreign policy address. In fact, Trump did not even mention Mexico or Mexican immigrants, which he had insulted incessantly during his presidential campaign once in his 3,496-word speech.

Instead Donald Trump, reading from a teleprompter - presumably intended to prevent him from veering off-script on a topic he has shown to have little knowledge about - tried to lay out a coherent foreign policy.

It did not work.

Donald Trump did speak in full sentences, did not insult anyone and did not brag about his personal success and wealth. But that alone does not make a coherent foreign policy platform.

Populism and contradictions

That is because the content of his speech did little to assuage worries about a Trump presidency. Essentially, his foreign policy speech was a repetition of his populist mantra "Make America great again/America First" coupled with a laundry list of contradictions and vague promises like these:

Trump told Washington's partners that "America is going to be a reliable friend and ally again” only to threaten to leave them high and dry should they not cough up more money for their own security in NATO and generally follow America's lead.

Trump wants to reconfigure NATO and force allies to pay more

Trump repeated his statement that he would get rid of the "Islamic State" terror group very quickly, preferably with the help of Middle Eastern countries, but again failed to give any specifics.

Trump threatened again to launch trade wars to create new or renegotiate existing trade agreements that are favorable to the United States, again without offering any details how and why US' trading partners might be willing to agree to such deals.

Trump said he wants the US not engaged in nation-building any longer and instead focused on putting America first. At the same time, he promised that under his leadership the US would continuously play the role of a peacemaker again. Once more, no specifics on how he intends to square that circle.

American version of Le Pen and Orban

European observers were shocked by what they heard from Trump on foreign policy.

"I came away, I must confess, with a vague sense of nausea," said Federiga Bindi, who holds the Jean Monnet Chair in European Political Integration at the University of Rome Tor Vergata. "Trump is the ultimate populist, he managed to mix elements of America-uber-alles, ultra-pacifism, acerbated militarism and gawkiness."

"I am European, and I heard the American version of Le Pen, Orban and other European populists who want to make us believe that working together through pooling sovereignty is the source of all evil," said Josef Janning, head of the Berlin office of the European Council on Foreign Relations.

Trump wants to defeat the Islamic State quickly, but how remains unclear

"As a student of US diplomatic history, it is profoundly troubling and disturbing to hear someone who is very likely to become the Republican party's flag bearer in the elections refer often and forcefully to America First, which by all accounts represents one of the darkest moments in American populism as it applies to international affairs," said Vincent Michelot, a political science professor at Sciences Po University in Lyon.

Trouble for Europe

If Trump's speech was envisaged as an effort to rebuild bridges with the Republican Party's foreign policy establishment which had blasted the candidate in an open letter last month, that also did not work, said Matthew Kroenig, a national security scholar at Georgetown University and a foreign policy advisor for Mitt Romney's 2012 presidential campaign.

"If this was meant to be a serious foreign policy speech, it did not deliver," said Kroenig. "If anything, this speech should make us more, not less, concerned about what a President Trump's foreign policy would look like."

For Europe specifically, noted Janning, the unilateralism and America first rhetoric espoused by Trump could mean "a lot of trouble for Europe as it may prompt US interventions in the Islamic world which will fail or have serious after effects."

Janning's French colleague Michelot was "alarmed and disheartened" by what he heard from the Republican frontrunner. But for Michelot at least, Trump's remarks served an - unintended - positive purpose:

"The speech also represents a confirmation that barring some catastrophic event in the summer or early fall, the next president of the United States will be a woman."