Power, Money, Territory: How Trump Shook the World in 50 Days

In a span of only 50 days, President Trump has done more than any of his modern predecessors to hollow out the foundations of an international system that the United States painstakingly erected in the 80 years since it emerged victorious from World War II.

Without formally declaring a reversal of course or offering a strategic rationale, he has pushed the United States to switch sides in the Ukraine war, abandoning all talk about helping a nascent, flawed democracy defend its borders against a larger invader. He did not hesitate when he ordered the United States to vote with Russia and North Korea — and against virtually all of America’s traditional allies — to defeat a U.N. resolution that identified Moscow as the aggressor. His threats to take control of the Panama Canal, Greenland, Gaza and, most incredibly, Canada, sound predatory, including his claim Tuesday that the border with America’s northern ally is an “artificial line of separation.”

He cut Ukraine off from arms and even American commercial satellite imagery, partly out of pique over his blowup in the Oval Office with President Volodymyr Zelensky, but largely because the Ukrainian president insists on a guarantee that the West would come to his country’s aid if Russia rebuilds and reinvades.

Mr. Trump has imposed tariffs on his allies after describing them as leeches on the American economy. And he has so damaged trust among the NATO allies that France is discussing extending its country’s small nuclear umbrella over Europe, and Poland is thinking of building its own atomic weapon. Both fear the United States can no longer be counted on to act as the alliance’s ultimate defender, a core role it created for itself when the NATO treaty was written.

No one knows how successful Mr. Trump will be in ripping asunder what every American president since Harry Truman has built — an era of institution-building that Mr. Truman’s secretary of state memorialized in a book entitled “Present At the Creation.” To live in Washington these days is to feel as if one is present at the destruction.