In one notable speech, on one memorable trip, we saw the clearest ever outline of what one might call the Trump Doctrine in foreign policy.

The current U.S. president doesn't tend to indulge in grand theory talk, but he effectively laid one out in Saudi Arabia.

It might be summed up as: less moralizing, more money. 

In other words, the pursuit of prosperity takes precedence over lofty rhetoric about democracy. This, in his telling, is a recipe for peace and stability.

Tuesday's speech in Riyadh was not, of course, the speech the last Republican president, George W. Bush, would have given for the first overseas trip of a presidential term.

Nor was it the speech Barack Obama gave in his first presidential address to the Arab world, when he spoke at length about democracy to university students in Cairo.

Trump spoke to a business crowd. And he, in contrast, disparaged Western do-gooders who travel around the world trying to spread democracy.

He had the CEOs on their feet applauding as he saluted the leadership of Saudi Crown Prince Mohammed bin Salman.

That's the same Mohammed bin Salman who was briefly treated as persona non grata in Washington for his suspected role in the murder and hacking to pieces of a columnist for the Washington Post.

"Commerce, not chaos," is how Trump described the Saudi leader's winning approach, before turning to criticize Western busybodies.

"It's crucial for the wider world to note, this great transformation [in Saudi Arabia] has not come from Western interventionists or flying people in beautiful planes giving you lectures on how to live and how to govern your own affairs," he said. 

"No, the gleaming marvels of Riyadh and Abu Dhabi were not created by the so-called nation-builders, neo-cons or liberal non-profits like those who spent trillions and trillions of dollars failing to develop Kabul, Baghdad, and so many other cities."

WATCH | Trump tours the Middle East:

Recapping Trump’s visit to Saudi Arabia

U.S. President Donald Trump secured economic commitments from Saudi Arabia on Tuesday during his tour of Gulf states. The two countries signed a nearly $142-billion U.S. defence agreement. CBC’s Chris Brown recaps Trump’s visit.

Trump ridiculed so-called nation-builders who, he said, wrecked more nations than they built, intervening in complex societies they did not understand.

The speech "might've been the clearest articulation of how Trump sees foreign policy," said Stephen Wertheim, a historian of U.S. foreign policy at the Carnegie Endowment for International Peace.

"He openly espoused transactionalism."

What this means for the rest of us

The address helped weave together loose threads in seemingly unrelated events of his presidency.

Gaza? In Trump's view, it should be a resort, rich with hotels and U.S. investors. Ukraine? President Volodymyr Zelenskyy got browbeaten in the White House, but has since signed a U.S.-Ukraine minerals deal and is back in Trump's better graces.

Trump announced hundreds of billions in business deals in Saudi Arabia and the UAE, including a massive investment in a sprawling data centre. During the trip, he also lifted sanctions on Syria, drawing a standing ovation led by the Saudi leader.

Does this approach make the world safer? Foreign policy thinkers interviewed for this story raised some pros, and cons, then, on balance, admitted they don't know.

"To be determined," said Wertheim, who sees some benefits — lower risk of a certain type of war, and fewer accusations of U.S. hypocrisy while promoting democracy but selectively choosing which autocrats to ally with. On the other hand, he says, allowing autocrats free rein is a potential recipe for instability.

"No one knows. Absolutely no one," said Daniel Immerwahr, a historian of U.S. foreign policy at Northwestern University. He agrees with Trump that nation-building has been destructive, but worries about a world where dictators abuse their citizens, and threaten neighbouring countries, without fear of the U.S., resembling the early 20th century.

Trump's values-light approach certainly has potential to make foreign affairs less, not more, predictable. 

Look no further than U.S. allies, and adversaries, now finding themselves confused about where they stand. Look at how he's blown hot and cold on NATO, on Ukraine and on China, imposing and removing tariffs, and swerving back and forth on restricting trade in high-tech products.

It can be hard to plan around that. Especially for the countries closest to the U.S., notably one, Canada, that he keeps talking about as some corporate takeover target.

Perhaps Canadians might draw limited reassurance from one rare thing Trump said he would do as a matter of principle: defend Canada if it were invaded.

"We protect Canada militarily and we always will. That's not a money thing," Trump said, during his White House meeting with Prime Minister Mark Carney.

There is some appeal to Trump's approach to foreign policy. Even his critics concede that. Two former Obama staffers, on their foreign-affairs podcast this week, saluted some things Trump is doing in the Middle East.

They said the traditional foreign-policy attitudes in Washington are, sometimes, not transactional enough; they applauded Trump for ignoring any criticism, including from ally Israel, and reopening ties with Syria.

"I think Trump deserves a lot of credit," Tommy Vietor said in his podcast Pod Save The World, adding that he likes the fact Trump doesn't care what Washington's foreign-policy "blob" thinks.

New York Times reporters in different parts of the Arab world chronicled the mixed reactions in a piece titled: "Trump's Pledge to the Middle East: No More 'Lectures on How to Live.'"

A human-rights lawyer told the paper that this is less hypocritical than the U.S. constantly talking about rights and democracy, and then selectively ignoring those things in places, and moments, that suit it. At least now, he said, the Americans are clear. Or are they? 

A consistent philosophy? Not exactly

There are still hypocrisies, or at the very least inconsistencies. The U.S. talks to autocrats and communists on several continents but, in part for domestic political reasons, shuts them out in Venezuela and Cuba.

That's one reason not to read too much into the speech, Wertheim says. It's not an iron-clad philosophy. Also, he says, Trump isn't as radical a change agent as he presents himself.

For example: the neoconservative impulse to spread democracy at gunpoint went out of fashion years ago. It's true, Joe Biden backed Ukraine, sending it arms; but, Wertheim added, he opposed Bush-style interventionism and actually pulled out of one such mission, in Afghanistan.

As for the potential effect of Trump's attitude on human rights, the Times also spoke to people in the Middle East worried about what it could mean.

One was the son of a 75-year-old U.S.-Saudi dual citizen, forbidden from leaving the kingdom after he was arrested, then released, over critical social-media posts. He said past U.S. administrations might have raised this with the Saudis. But he said he hasn't managed to get anyone in the Trump administration to talk to him.

On their podcast, the ex-Obama staffers said there's a third approach. A middle ground between military adventurism and democracy-at-gunpoint, and, on the other end, the near-total indifference to democratic values.

"We shouldn't let [Trump's] accurate disregard for American interventionism lead you to believe that the only alternative is a bunch of, let's face it, a bunch of … white American CEOs and a bunch of royals sitting around and deciding everything themselves either," Ben Rhodes said.

"There needs to be a voice for people in these discussions in this part of the world."

The podcast episode was titled, "Con Man Air: Trump's Middle East Cash Grab," reflecting a jaundiced view of this Mideast trip as a grift for Trump and his family.

It could just as easily have been a reference to the animating philosophy of Trump's foreign policy. 

Unlike Ronald Reagan, who spoke of America as a shining city on a hill, Trump speaks of a different gleam — of a golden age, animated by a simpler, clearer philosophy: Follow the money. Where ideals are out, and the art of the deal is in.