The idea of America as an exceptional nation is often expressed by the phrase “a shining city on a hill.” But people forget how John Winthrop first used this description in 1630 as he addressed his ship of Pilgrims setting sail for the New World: “We shall be as a city upon a hill, the eyes of all people are upon us.”

The eyes of the world are most certainly upon America today, but many foreign observers describe a once-shining city that seems to be going dark. They see President Donald Trump transforming America’s foreign policy and its image abroad. In place of a mushy but globally admired internationalism, Trump celebrates the narrow, transactional values of a real estate dealmaker. He behaves as if generosity is for suckers. In his world, strong countries inevitably dominate weak ones, and might makes right.

Here’s the big question: As Trump takes the wrecking ball to the old version of American foreign policy, what does he intend to construct in its place? His career shows little evidence of strategic thinking. He has been a disrupter and dealmaker rather than a builder.

The best assessment of Trump’s strategic “vision” that I’ve seen comes from Alex Younger, a former head of the British intelligence service known as MI6. He said in a Feb. 21 interview that “we are in a new era where, by and large, international relations aren’t going to be determined by rules and multilateral institutions. They’re going to be determined by strong men and deals.”

Younger likened Trump’s strong-arm diplomacy to the 1945 Yalta Conference, in which the dominant wartime leaders - President Franklin D. Roosevelt, Soviet leader Joseph Stalin and British Prime Minister Winston Churchill - carved up Europe without regard for the desires of smaller nations.

The obvious example of this neo-Yalta mentality is the way Trump has conducted the preliminary phase of Ukraine peace negotiations. He has muscled a weak Ukrainian president in Volodymyr Zelensky (“You don’t have the cards”) to accommodate what he sees as the interests of the power players: the United States and Russia. In pursuing this peace agreement, he proclaims that “China can help,” too.

Trump seems to envision a new balance of power with three poles: the United States plus Russia and China, whose leaders he sees as kindred spirits. The rest of the world must fend for itself.

The world doesn’t get a vote about American politics, but it has strong opinions. A European survey released this month showed that favorability toward the United States has plummeted in Britain, Denmark, France, Germany, Italy, Spain and Sweden. In Canada, only 1 in 3 people have a positive view of Trump’s America.

What has astonished the world is how quickly Trump has reversed the United States’ long-standing commitments. Secretary of State Marco Rubio boasted on Monday that he had cut 83 percent of USAID programs. Trump cut military and intelligence support for Ukraine to squeeze concessions. He dismantled U.S. opposition to Vladimir Putin’s Russia so fast that a Kremlin spokesman exclaimed: “The new administration is rapidly changing all foreign policy configurations. This largely aligns with our vision.”

Trump may be making a big mistake with his disdain for Europe - which seems to be finding its voice after decades of passively following in Washington’s wake. European leaders tell me they are so worried about an expansionist Russia that they are prepared to take a strong stand in Ukraine by committing to send troops there to deter further aggression after a ceasefire.

Trump’s global economic strategy is better defined than his foreign policy goals but no less destabilizing. He proposes a restoration of tariff barriers erected in the late 19th century, when the United States was trying to build up its manufacturing industries against European competition. In theory, re-creating similar tariff walls would drive up import prices so much that investors would rush to build new manufacturing plants and launch Trump’s “Golden Age of America.” But that process - the “period of transition,” as Trump called it this week - is likely to take many years.

Let’s imagine that Trump’s tariff walls succeed in withdrawing the United States from the existing international trading system. How would the rest of the world react? Initially, other countries would impose their own tariffs, as Canada, Mexico and China are already doing. But over time, these nations would probably form trading coalitions - with Europe and the Global South making trade deals with an increasingly dominant China and avoiding Fortress America.

“The eyes of all people are upon us,” as Winthrop said. As his ship departed from England for the magnificent wilderness and freedom that America offered, he admonished his colleagues that if they worshiped the false god of “pleasure and profits,” then “we shall surely perish out of the good land.”

That’s the burden of exceptionalism: It requires people to behave in exceptional ways.