Standing side by side with President Vladimir Putin, U.S. President Donald Trump refused Monday to blame the Russian leader for meddling in the 2016 U.S. election, casting doubt on the findings of his own intelligence agencies and sparking a storm of criticism at home.

Although he faced pressure from critics, allied countries and even his own staff to take a tough line, Trump spoke not a single disparaging word in public about Moscow on any of the issues that have brought relations between the two powers to their lowest ebb since the Cold War.

Former CIA Director John Brennan denounced Trump's performance as "treasonous," while Republican U.S. Sen. John McCain called the meeting with Putin a "tragic mistake," although some other Republicans were more cautious.

Merriam-Webster dictionary tweeted that the top-searched words after the summit included “treason,” “traitor” and “collusion.” Not to be outdone, Dictionary.com got involved and tweeted to clarify the meanings of the two words that start trending after the meeting: “Treason summit.”

Under Article II, Section 4 of the U.S. Constitution, a president can be impeached upon the “Conviction of, Treason, Bribery, or other High Crimes and Misdemeanors.” The House brings those formal charges against the president, and then the whole circus moves over to the Senate, which acts as the trier of fact. The Senate then hears evidence and makes the decision whether to convict and remove from office (by a two-thirds majority).

However, the treason statute, 18 U.S.C. § 2381, would be a tough case to make:

“Whoever, owing allegiance to the United States, levies war against them or adheres to their enemies, giving them aid and comfort within the United States or elsewhere, is guilty of treason and shall suffer death, or shall be imprisoned not less than five years and fined under this title but not less than $10,000; and shall be incapable of holding any office under the United States.”

Key moments from the Trump-Putin press conference

Here is a full transcript of the exchange in question:

REPORTER, AP: President Trump, you first. Just now, President Putin denied having anything to do with the election interference in 2016. Every U.S. intelligence agency has concluded that Russia did. My first question for you sir is, who do you believe? My second question is would you now, with the whole world watching, tell President Putin, would you denounce what happened in 2016 and would you want him to never do it again?

TRUMP: So let me just say that we have two thoughts. You have groups that are wondering why the FBI never took the server. Why haven't they taken the server? Why was the FBI told to leave the office of the Democratic National Committee?

I've been wondering that. I've been asking that for months and months and I've been tweeting it out and calling it out on social media. Where is the server? I want to know where is the server and what is the server saying?

With that being said, all I can do is ask the question.

My people came to me, Dan Coates, came to me and some others they said they think it's Russia. I have President Putin. He just said it's not Russia.

I will say this: I don't see any reason why it would be. But I really do want to see the server but I have, I have confidence in both parties.

I really believe that this will probably go on for a while but I don't think it can go on without finding out what happened to the server. What happened to the servers of the Pakistani gentleman that worked on the DNC?

Where are those servers? They're missing. Where are they? What happened to Hillary Clinton's emails? 33,000 emails gone, just gone. I think in Russia they wouldn't be gone so easily.

I think it's a disgrace that we can't get Hillary Clinton's 33,000 emails.

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 and what he did is an incredible offer.

He offered to have the people working on the case come and work with their investigators, with respect to the 12 people. I think that's an incredible offer. OK? Thank you.