Arizona Sen. John McCain condemned President Donald Trump’s remarks at a joint press conference with Russian President Vladimir Putin in Helsinki on Monday, calling it “one of the most disgraceful performances by an American president in memory.”

“The damage inflicted by President Trump’s naiveté, egotism, false equivalence, and sympathy for autocrats is difficult to calculate. But it is clear that the summit in Helsinki was a tragic mistake,” McCain said in a statement. “President Trump proved not only unable, but unwilling to stand up to Putin. He and Putin seemed to be speaking from the same script as the president made a conscious choice to defend a tyrant against the fair questions of a free press, and to grant Putin an uncontested platform to spew propaganda and lies to the world.”

On Friday, McCain called for Trump to cancel the summit if he was “not prepared to hold Putin accountable” after the Justice Department charged 12 Russian intelligence officials with hacking the Democratic National Committee’s emails, Hillary Clinton’s campaign and state election systems.

On Monday, Trump met with Putin for two hours and then, during a 46-minute joint press conference, slammed Special Counsel Robert Mueller’s investigation into Russian meddling in the 2016 U.S. presidential election and declined to criticize Putin for election interference.

“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 said during Monday’s press conference, when asked whether he believed U.S. intelligence officials over Putin, who denied any election meddling.

McCain joined other congressional Republicans on Monday in contradicting Trump and acknowledging Russia’s interference in the 2016 presidential election.

“No prior president has ever abased himself more abjectly before a tyrant,” McCain said in his statement. “Not only did President Trump fail to speak the truth about an adversary; but speaking for America to the world, our president failed to defend all that makes us who we are—a republic of free people dedicated to the cause of liberty at home and abroad.”

Read McCain’s full statement here:

“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 naiveté, egotism, false equivalence, and sympathy for autocrats is difficult to calculate. But it is clear that the summit in Helsinki was a tragic mistake. “President Trump proved not only unable, but unwilling to stand up to Putin. He and Putin seemed to be speaking from the same script as the president made a conscious choice to defend a tyrant against the fair questions of a free press, and to grant Putin an uncontested platform to spew propaganda and lies to the world. “It is tempting to describe the press conference as a pathetic rout – as an illustration of the perils of under-preparation and inexperience. But these were not the errant tweets of a novice politician. These were the deliberate choices of a president who seems determined to realize his delusions of a warm relationship with Putin’s regime without any regard for the true nature of his rule, his violent disregard for the sovereignty of his neighbors, his complicity in the slaughter of the Syrian people, his violation of international treaties, and his assault on democratic institutions throughout the world. “Coming close on the heels of President Trump’s bombastic and erratic conduct towards our closest friends and allies in Brussels and Britain, today’s press conference marks a recent low point in the history of the American Presidency. That the president was attended in Helsinki by a team of competent and patriotic advisors makes his blunders and capitulations all the more painful and inexplicable. “No prior president has ever abased himself more abjectly before a tyrant. Not only did President Trump fail to speak the truth about an adversary; but speaking for America to the world, our president failed to defend all that makes us who we are—a republic of free people dedicated to the cause of liberty at home and abroad. American presidents must be the champions of that cause if it is to succeed. Americans are waiting and hoping for President Trump to embrace that sacred responsibility. One can only hope they are not waiting totally in vain.”

Get our Politics Newsletter. The headlines out of Washington never seem to slow. Subscribe to The D.C. Brief to make sense of what matters most. Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Write to Katie Reilly at Katie.Reilly@time.com.