For the last week on the road, President Trump had been measured, disciplined and studiously scripted as he picked his way through the geopolitical minefields of Asia.
Then came the weekend.
In a stream of tweets on Sunday, the president said those who want to probe his ties to Russia were “haters and fools,” ridiculed “crooked” Hillary Clinton’s ill-fated effort to reset relations with Russia and fired back at North Korea’s leader, Kim Jong-un, for calling him old, saying that he could call Mr. Kim “short and fat” — but had restrained himself.
That followed a freewheeling session with reporters on Air Force One on Saturday, in which Mr. Trump dismissed the Russia investigation as a Democratic “hit job” and derided as “political hacks” three former chiefs of the nation’s intelligence agencies, all three of which concluded that Russia had meddled in the 2016 presidential election.
It was hard to say what prompted the sudden change in the president’s demeanor, though the first lady, Melania Trump, who often plays a moderating influence on her husband, dropped off the trip in Beijing, after visiting the Great Wall of China and stroking the paw of a panda bear at the Beijing Zoo. Mr. Trump, 71, could also simply be tired.
Pressed again on Sunday whether he believed President Vladimir V. Putin’s denials that Russia had intervened, Mr. Trump seemed to walk back his earlier comments somewhat. He said he did not dispute the assessment of the intelligence agencies that it had interfered
“As to whether I believe it or not, I’m with our agencies, especially as currently constituted, with their leadership,” Mr. Trump said at a news conference with Vietnam’s president, Tran Dai Quang. “I believe in our agencies. I’ve worked with them very strongly.”
Still, Mr. Trump’s endorsement was grudging — he noted that the assessment reflected only four agencies, not 17 — and he repeated his assertion that Washington needed to move on from the Russia investigation to cooperate with the Russians on issues from North Korea to Syria.
“What I believe is, we have to get to work,” he said. “It’s now time to get back to healing a world that is shattered and broken.”
In the short run, Mr. Trump’s comments broke with a narrative that the White House had carefully constructed during this 12-day trip — that of a statesman marshaling a worldwide coalition to confront a nuclear North Korea, and a populist leader working to right trade imbalances.
The president’s tweets and comments also complicated life for White House officials, who had been encouraged by his friendly meetings with the leaders of Japan, China and South Korea and by what they characterized as one of the most effective foreign-policy speeches of his presidency, on the need to confront a nuclear North Korea.