After five weeks in which President Trump made clear his determination to scrap America’s traditional sources of power — its alliances among like-minded democracies — and return the country to an era of raw great-power negotiations, he left one question hanging: How far would he go in sacrificing Ukraine to his vision?

The remarkable shouting match that played out in front of the cameras early Friday afternoon from the Oval Office provided the answer.

As Mr. Trump admonished President Volodymyr Zelensky and warned him that “you don’t have the cards” to deal with President Vladimir V. Putin of Russia, and as Vice President JD Vance dressed down the Ukrainian leader as being “disrespectful” and ungrateful, it was clear that the three-year wartime partnership between Washington and Kyiv was shattered.

Whether it can be repaired, and whether a deal to provide the United States revenue from Ukrainian minerals that was the ostensible reason for the visit can be pieced back together, remains to be seen.

But the larger truth is that the venomous exchanges — broadcast not only to an astounded audience of Americans and Europeans who had never seen such open attacks on each other, but to Mr. Putin and his Kremlin aides — made evident that Mr. Trump regards Ukraine as an obstacle to what he sees as a far more vital project.

What Mr. Trump really wants, one senior European official said this week before the blowup, is a normalization of the relationship with Russia. If that means rewriting the history of Moscow’s illegal invasion three years ago, dropping investigations of Russian war crimes or refusing to offer Ukraine long-lasting security guarantees, then Mr. Trump, in this assessment of his intentions, is willing to make that deal.

To anyone listening carefully, that goal was bubbling just beneath the surface as Mr. Zelensky headed to Washington for his disastrous visit.

Secretary of State Marco Rubio — once a defender of Ukraine and its territorial sovereignty, now a convert to the Trump power plays — made clear in an interview with Breitbart News that it was time to move beyond the war in the interest of establishing a triangular relationship between the United States, Russia and China.

“We’re going to have disagreements with the Russians, but we have to have a relationship with both,” Mr. Rubio said. He carefully avoided any wording that would suggest, as he often said as a senator, that Russia was the aggressor, or that there was risk that, if not punished for its attack on Ukraine, it might next target a NATO nation.

“These are big, powerful countries with nuclear stockpiles,” he said of Russia and China. “They can project power globally. I think we have lost the concept of maturity and sanity in diplomatic relations.”

Mr. Trump makes no secret of his view that the post-World War II system, created by Washington, ate away at American power.

Above all else, that system prized relationships with allies committed to democratic capitalism, even maintaining those alliances that came with a cost to American consumers. It was a system that sought to avoid power grabs by making the observance of international law, and respect for established international boundaries, a goal unto itself.

To Mr. Trump, such a system gave smaller and less powerful countries leverage over the United States, leaving Americans to pick up far too much of the tab for defending allies and promoting their prosperity.

While his predecessors — both Democrats and Republicans — insisted that alliances in Europe and Asia were America’s greatest force multiplier, keeping the peace and allowing trade to flourish, Mr. Trump viewed them as a bleeding wound. In the 2016 presidential campaign, he repeatedly asked why America should defend countries running trade surpluses with the United States.

In the five weeks since his second inauguration, Mr. Trump has begun exercising a plan to destroy that system. It explains his demand that Denmark cede control of Greenland to the United States, and that Panama return a canal that Americans built. When asked how he could seize sovereign territory in Gaza for redevelopment in his plan for a “Riviera of the Middle East,” he shot back, “Under the U.S. authority.”

But Ukraine was always a more complicated case. Only 26 months ago, Mr. Zelensky was feted in Washington as a warrior for democracy, invited to address a joint meeting of Congress and applauded by Democrats and Republicans alike for standing up to bald aggression by a murderous foe.

Mr. Trump and Mr. Vance had signaled for months that in their minds the American commitment to Ukraine’s sovereignty was over. Three weeks ago, Mr. Trump told an interviewer that Ukraine, a former Soviet republic that had embraced its independence, built close ties to Western Europe and sought to join NATO, “may be Russian someday.”

To the shock of America’s allies, Mr. Vance traveled to the Munich Security Conference two weeks ago and said nothing about assuring that any armistice or cease-fire would come with security guarantees for Ukraine, or about Russia paying any price for its invasion.

Instead, Mr. Vance seemed to embrace the rising far-right party in Germany and its counterparts throughout Europe. Gone was the Biden-era talk about sticking with Ukraine “as long as it takes” to deter any temptation by Russia to carry the war farther West.

Mr. Zelensky saw all this, of course — he was at Munich, too — but clearly he did not read the room the way his European supporters did. While President Emmanuel Macron of France and Prime Minister Keir Starmer of Britain preceded him to the Oval Office with elaborate plans to placate Mr. Trump, and explain how Europe was stepping up its own military spending, Mr. Zelensky took the bait, especially when Mr. Vance began mocking Ukraine’s efforts to recruit troops.

He got combative, telling Mr. Trump that the oceans between America and Russia would not protect it forever. Mr. Trump raised his voice, and told the Ukrainian that he would be lucky just to get a cease-fire, suggesting that any terms — or no terms — would be better than his inevitable defeat.

“I want to see guarantees,” Mr. Zelensky retorted. And minutes later, he left the White House, his luncheon of rosemary roasted chicken and creme brulee uneaten, the minerals deal unsigned and his country’s future ability to fend off a renewed Russian push to topple Kyiv in doubt.

Almost immediately, the world retreated to its familiar corners.

Mr. Macron, siding with the Ukrainian leader, urged that the West thank the Ukrainians for being the forward defense of freedom. He was joined by the nervous Eastern Europeans, led by Poland, Lithuania and Latvia. But in private, several European diplomats said they thought the damage might be irreparable.

The Russians celebrated their good luck. Former President Dmitri A. Medvedev thanked Mr. Trump for “telling the truth” to Mr. Zelensky’s face. He urged him to suspend remaining American aid.

Mr. Rubio was among the first to congratulate the president for putting in his place a man the secretary of state used to applaud as a modern-day Churchill in a T-shirt.

“Thank you @POTUS for standing up for America in a way that no President has ever had the courage to do before,” Mr. Rubio wrote on social media. “Thank you for putting America First.”

Of course, it is far easier to repeat Mr. Trump’s favorite slogan, and to blow up an existing world order, than to create a new one. It took decades to assemble the post-World War II rules of global engagement, and for all its faults, the system succeeded at its primary objectives: avoiding great power war and encouraging economic interdependence.

Mr. Trump has never articulated at any length what he would replace those rules with, other than that he would use America’s military and economic power to strike deals — essentially an argument that keeping the peace is as simple as weaving together minerals agreements and trade pacts, maybe with a few real estate transactions thrown in.

There is little precedent to suggest that approach alone works, especially in dealing with authoritarian leaders like Mr. Putin and President Xi Jinping of China, who take a long view in dealing with democracies that they view as lacking the sustained will necessary to achieve difficult objectives.

But judging by Friday’s display in the Oval Office, Mr. Trump seems convinced that as long as he is at the helm, the world will order itself as he commands.