"The president of the United States essentially capitulated, and seems intimidated by Vladimir Putin", said James Clapper, a career intelligence official who served as director of national intelligence through the 2016 race.
Trump spoke of the 2016 electoral college map and of online conspiracy theories created to undermine an ongoing investigation into Russia's role in the race, questioning why law enforcement failed to seize Democratic National Committee servers that were hacked by Russian military intelligence officers and whether it was that organization - not his campaign - that had conspired with Moscow to lose the election.
Hannity also revisited a question that came up during the news conference - whether or not the Russians had compomising information on him. The mainstream USA media also expressed outrage.
"Don't make the relationship between Russian Federation and the United States - don't hold it hostage of this internal political struggle", he said, adding that "it's nothing to be proud of for American democracy, to use such dirty methods in the political rivalry".
Hours after the Helsinki summit, Trump tweeted: "I have GREAT confidence in MY intelligence people".
"However, I also recognize that in order to build a brighter future, we can not exclusively focus on the past - as the world's two largest nuclear powers, we must get along".
Republican Patriots: "Where are you???" tweeted John Brennan, said former Central Intelligence Agency director John Brennan.
"The damage inflicted by President Trump's naivete, egotism, false equivalence, and sympathy for autocrats is hard to calculate", McCain said in a blistering statement.
Even as he rejected the notion that Russian Federation had interfered in the election, Putin defended the veracity of the information that was revealed in the Democratic National Committee's hacked emails, which were made public by WikiLeaks in July 2016.
Speaking on Monday, President Putin offered to allow USA investigators to visit Russian Federation to question the officers.
On Monday, Trump also resurrected several debunked conspiracy theories about his opponent Hillary Clinton and the Democratic Party, called out an Federal Bureau of Investigation agent involved in the meddling probe by name and complained about media coverage. The US leader said a productive dialogue between America and Russian Federation is good for both countries and "is good for the world". It gave no further details.
The US leader, bent on forging a personal bond with the Kremlin chief despite the election allegations, went into the summit blaming the "stupidity" of his predecessors for plunging ties to their present low.
That is what a real American president, sworn to protect and defend the Constitution, would have said to Putin.
His comments in Helsinki have sparked such anger in America that the U.S. political elite is likely to view any attempt by the Trump administration to mend fences with Moscow with the deepest suspicion. Asked if Russian Federation was at all to blame for the poor ties, he said: "I hold both countries responsible".
Carlson said one of NATO's initial objectives was to keep the Soviets from encroaching on Western Europe - but now, if a nation such as Montenegro is threatened by another country, Carlson's children could be tasked to defend the tiny North Atlantic Treaty Organisation nation to no direct USA benefit.
A lot of the questions focused on Russia's intrusion into the USA election campaign (the considered position of the key U.S. intelligence agencies) and specifically the indictment by the Mueller probe of 12 Russian intelligence agents.
"I beat Hillary Clinton easily and frankly we beat her..."
Trump's warm words for Russian Federation were a marked contrast from the past week, when he repeatedly rebuked long-standing US allies at a North Atlantic Treaty Organisation summit and during a visit to Britain.
After the lunch, Trump and Putin will appear for a joint news conference in Helsinki.
Presidents Donald Trump and Vladimir Putin vowed a fresh start to troubled relations between the world's greatest nuclear powers at their first summit on Monday, as the American leader rejected a chance to condemn Moscow's alleged manipulation of USA elections.
While Republican Senator Jeff Flake said, "I never thought I would see the day when our American president would stand on the stage with the Russian president and place blame on the United States for Russian aggression".
A post-NATO trip to Britain, supposedly America's partner in a "special relationship", was riddled with controversy as well. He referred to the European Union as a "foe" in trade and repeatedly criticized it.
CBS' Margaret Brennan said she was messaging some US officials during the speech who said they were turning off the television.