The phone conversation with President Volodymyr Zelensky of Ukraine that prompted his impeachment — “I would like you to do us a favor, though” — exposed the transactional mentality behind much of Mr. Trump’s worldview.
This was the same president who in the first days of his administration angrily pushed the Australian prime minister to cancel an immigration deal he had made with President Barack Obama because otherwise Mr. Trump would be “seen as a weak and ineffective leader in my first week,” or the president who, according to John Bolton, the former national security adviser, asked China’s president, Xi Jinping, to buy more American soybeans and wheat to help the president with the farm vote.
The niceties of diplomatic communications have been alien to the star of “The Apprentice.” According to Carl Bernstein, writing for CNN, Mr. Trump called the British prime minister, Theresa May, a “fool” and Chancellor Angela Merkel of Germany “stupid” in phone calls. Among other insults, Mr. Trump called Prime Minister Justin Trudeau of Canada “very dishonest & weak” in a tweet and accused President Emmanuel Macron of France of making “very, very nasty” remarks.
These were close allies. The tone is very different with the bad guys. Mr. Kim, arguably the nastiest despot on earth, made a striking metamorphosis from “little rocket man” to writer of “love letters” in Mr. Trump’s universe after two summit meetings that achieved nothing.
The relationship with Mr. Xi went the other way. Before Mr. Trump decided to heap all his coronavirus woes on China, he had repeatedly praised its leader — “Terrific working with President Xi, a man who truly loves his country.”
In fact, there doesn’t seem to be an illiberal leader Mr. Trump doesn’t admire. The president of the Philippines, Rodrigo Duterte, who has led a campaign against drug dealers and users linked to thousands of extrajudicial killings, was doing an “unbelievable job on the drug problem.” Viktor Orban, the autocratic prime minister of Hungary, was “respected all over Europe.” Recep Tayyip Erdogan, the authoritarian president of Turkey who often telephones Mr. Trump, “has become a friend of mine.” When Crown Prince Mohammed bin Salman of Saudi Arabia became a global pariah over the murder of the journalist Jamal Khashoggi, Mr. Trump came to his rescue. “I saved his ass,” the president said, according to a book by Bob Woodward. “I was able to get Congress to leave him alone.”
All this has been exhaustively chronicled in Mr. Trump’s tweets and declarations and in the rapidly swelling library of tell-all books by outcasts from the revolving door of aides like Mr. Bolton, the impeachment hearings, the dossier compiled by Robert Mueller III or books like Mr. Woodward’s. Yet in all this sound and fury, one mystery stands out. And that is the source of Mr. Trump’s curious reticence before Mr. Putin.