If President Biden wanted an example of a summit that did not go according to plan, he needed only to look back to 2018.
That year, President Donald J. Trump flew to Helsinki to meet President Vladimir V. Putin of Russia, the first face-to-face meeting between the two and a highly anticipated moment given the then-ongoing investigations of Russian interference and cooperation with Mr. Trump’s 2016 presidential campaign.
It might have been a chance for Mr. Trump to push back against those accusations by offering a forceful denunciation of Russia’s actions in private, and again during a joint news conference by the two men.
Instead, standing on the stage by Mr. Putin’s side, Mr. Trump dismissed the conclusions by U.S. intelligence agencies about Russian meddling and said, in essence, that he believed Mr. Putin more than he did the C.I.A. and other key advisers
“They said they think it’s Russia,” Mr. Trump said. “I have President Putin; he just said it’s not Russia.” He added that he didn’t see any reason Russia would have been responsible for hacks during the 2016 election. “President Putin was extremely strong and powerful in his denial today.”
It was the kind of jaw-dropping assertion that U.S. administrations usually strive to avoid in the middle of highly scripted presidential summits. Critics lashed out at Mr. Trump for undermining his own government and for giving aid and comfort to an adversary. Even Republican allies of the president issued harsh denunciations.
“It is the most serious mistake of his presidency and must be corrected — immediately,” said Newt Gingrich, the former Republican House speaker and a staunch supporter of Mr. Trump.
There was nothing about the one day Helsinki summit that was normal. Mr. Putin and Mr. Trump were so chummy that the Russian president gave Mr. Trump a soccer ball to take home as a gift. Mr. Trump thanked him and bounced the ball to Melania Trump, the first lady, in the front row, saying he would take it home to give it to his son, Barron.
(Sarah Sanders, the White House press secretary at the time, later issued a statement saying that the ball — like all gifts — had been examined to make sure it had not been bugged with listening devices.)
In a statement issued as Mr. Biden headed to Europe last week, Mr. Trump once again called his meeting with Mr. Putin “great and very productive” and he defended supporting the Russian president over his intelligence aides.
“As to who do I trust, they asked, Russia or our ‘Intelligence’ from the Obama era,” he said in a statement. “The answer, after all that has been found out and written, should be obvious. Our government has rarely had such lowlifes as these working for it.”
The former president also took a shot at his successor in the statement, warning him not to “fall asleep during the meeting.”
One thing was certain — Mr. Biden did not follow through on Mr. Trump’s request that when Mr. Biden met with Mr. Putin “please give him my warmest regards!”