Video report by ITV News Correspondent Juliet Bremner
After US president Donald Trump openly questioned his own intelligence agencies’ finding that Russia meddled in the 2016 US election, criticism has come in strong and fast from his allies and foes.
While Trump's political leanings have caused outrage this is the first time senior officials have questioned whether his comments qualify as "treasonous".
So, could the President's defence of Russia get him impeached?
How has Trump defended his defence of Russia?
In an interview with Fox News’ Sean Hannity broadcast on Monday evening, Mr Trump said “it’s a shame” that he and Putin were being asked questions about the Russia probe while they were trying to discuss issues like Syria and nuclear proliferation.
“We’ve had a phony witch hunt deal drive us apart,” he said.
Fellow Republican politicians have generally stuck with Mr Trump during a year and a half of turmoil, but he was assailed as seldom before as he returned home on Monday night from what he had hoped would be a proud summit with Putin.
How have allies and critics reacted?
Senator John McCain of Arizona was most outspoken, declaring that Mr Trump made a “conscious choice to defend a tyrant” and achieved “one of the most disgraceful performances by an American president in memory”.
House Speaker Paul Ryan, who rarely criticises Mr Trump, stressed there was “no question” that Russia had interfered.
Even staunch Mr Trump backer Newt Gingrich, the former House speaker, called the president’s comments “the most serious mistake of his presidency” and said they “must be corrected — immediately”.
Trump has caused outrage before. Why is this different?
The former CIA director described the President's press conference as "nothing short of treasonous."
His tweet refers to the US Constitution's grounds for impeachment, which are "treason, bribery, and other high crimes and misdemeanours."
Clarifying whether Trump's actions qualify as "treason, bribery, and other high crimes and misdemeanours" is up to Congress.
It would also require the Republican-controlled Senate and House to agree on whether the grounds for impeachment have been met.
What exactly has Trump said?
Standing alongside Mr Putin in Helsinki, Mr Trump steered clear of any confrontation with the Russian, going so far as to question American intelligence and last week’s federal indictments that accused 12 Russians of hacking into Democratic email accounts to hurt Hillary Clinton in 2016.
“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.
“He just said it’s not Russia. I will say this: I don’t see any reason why it would be,” Mr Trump said.
As he flew home to Washington aboard Air Force One, Mr Trump tried to clarify his position via tweet, saying: “As I said today and many times before, ‘I have GREAT confidence in MY intelligence people.’ However, I also recognise that in order to build a brighter future, we cannot exclusively focus on the past – as the world’s two largest nuclear powers, we must get along!”
How did US National Intelligence react?
His scepticism drew a quick formal statement — almost a rebuttal — from Mr Trump’s director of national intelligence, Dan Coats.
“We have been clear in our assessments of Russian meddling in the 2016 election and their ongoing, pervasive efforts to undermine our democracy, and we will continue to provide unvarnished and objective intelligence in support of our national security,” Mr Coats said.
What has Vladimir Putin said?
The two leaders’ long-awaited summit began with a private face-to-face sit-down — just the leaders and their interpreters — that lasted more than two hours, before additional meetings joined by senior aides.
The pair had held lengthy talks before — on the sidelines of world leader meetings in Germany and Vietnam last year — but this was their first official summit and was being watched closely, especially following the announcement of new indictments against 12 Russian intelligence officers accused of hacking Democratic emails to help the Trump campaign.
Asked about the indictments, Mr Putin suggested that Moscow and Washington could jointly conduct the investigation, inviting special counsel Robert Mueller’s investigators to come to Russia to interview the 12 people — an idea Mr Trump hailed as an “incredible offer”.
Putin said he’d expect the US to return the favour and cooperate in the Russian probe against William Browder, a British investor charged with financial crimes in Russia.
Browder, an outspoken Putin critic, was a driving force behind a US law targeting Russian officials over human rights abuses.