Donald Trump returned late Monday from his European tour to face ire in Washington, where US intelligence officials and senior Republicans were denouncing the president as "shameful" and "disgraceful" after he refused to challenge Russian leader Vladimir Putin over interference in American elections.
Republican Senator John McCain said Trump's seeming acceptance of Putin's denial was a historical "low point" for the US presidency and the Helsinki summit between the two leaders a "tragic mistake."
"Today's press conference in Helsinki was one of the most disgraceful performances by an American president in memory. The damage inflicted by President Trump's naivete, egotism, false equivalence, and sympathy for autocrats is difficult to calculate," McCain said in a blistering statement.
"No prior president has ever abased himself more abjectly before a tyrant."
Taking direct issue with the president who appointed him, Director of National Intelligence Dan Coats said US spy agencies have been "clear" and "fact-based" in their assessment that Moscow interfered in the presidential race two years ago -- an assessment that Trump refused to endorse in Helsinki.
Coats added that Russia remains behind "ongoing, pervasive efforts to undermine our democracy."
Trump stunned US political allies and foes alike with his answer to a question about Russian hacking and interference in the 2016 election which saw him defeat Democrat Hillary Clinton.
Putin "just said it is not Russia. I will say this: I don't see any reason why it would be," Trump said.
That came three days after the US Justice Department indicted 12 Russians for hacking Democratic Party computers, the latest in a series of actions taken by the US government since late 2016 in retribution for what intelligence agencies say was a broad plan to support Trump's election campaign directed by Putin himself.
Yet Trump appeared to take Putin's word in dismissing that conclusion.
"I have great confidence in my intelligence people. But I will tell you that President Putin was extremely strong and powerful in his denial today."
Trump also appeared to embrace Putin's offer to have Russian investigators work together with US prosecutors on the case of the 12 just indicted.
"I think that's an incredible offer."
Astonished Republicans and Democrats uniformly condemned Trump, with harsh criticism coming even from hosts on Fox News -- a network normally friendly to the president.
"The president must appreciate that Russia is not our ally," said Republican House Speaker Paul Ryan.