In a shocking press conference with Russian leader Vladimir Putin, President Donald Trump said he didn’t “see any reason why” Russia would have meddled in the 2016 election. Instead of criticizing the Kremlin over its illegal annexation of Crimea and support for separatists in eastern Ukraine, the president blamed both the U.S. and Russia for the strained state of relations, and called Robert Mueller’s investigation a “disaster for our country.”

Arizona senator John McCain described the 45-minute press conference as “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 statement. “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.”

“No prior president has ever abased himself more abjectly before a tyrant.”

McCain’s condemnation was the most forceful among Republican lawmakers, many of whom also reaffirmed the intelligence community assessment that Russia did interfere in the 2016 election.

During the Helsinki press conference, Trump said that members of his administration told him that Russia interfered—but he appeared to side with Putin over them. “My people came to me, Dan Coats came to me and some others, they said they think it's Russia,” Trump said. “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.”

Noting his “great confidence in my intelligence people,” Trump nonetheless described Putin’s denial of election interference as “extremely strong and powerful.” His refusal to acknowledge Russian election interference is at odds with the words and actions of his administration.

On Friday, Director of National Intelligence Dan Coats described Russia as the “most aggressive” foreign cyber foe targeting America. Earlier that day, the Department of Justice announced charges against 12 Russian intelligence agents over alleged efforts to hack into Democratic networks. The indictment is part of special counsel Robert Mueller’s investigation into election interference.

“President Trump missed an opportunity to publicly press President Putin on whether he would agree to extradite the defendants to the United States to answer allegations in court,” said Senate Judiciary chairman Chuck Grassley. “It should always be the goal of U.S. president to improve relations with other countries, especially ones as large and strategically important as Russia. It’s also important for our leaders to be clear-eyed in their approach.”

Texas congressman Will Hurd, a former CIA officer, suggested that Putin had successfully manipulated the president.

“I've seen Russian intelligence manipulate many people over my professional career and I never would have thought that the US President would become one of the ones getting played by old KGB hands,” he said on Twitter .

Senate Foreign Relations Committee chairman Bob Corker told reporters that Trump’s remarks “made us look as a nation more like a pushover.” “I did not think this was a good moment for our country," he said, later adding, “This was a very good day for President Putin.”

South Carolina senator Lindsey Graham described the press conference as a “missed opportunity” to hold Russia accountable for election interference. “This answer by President Trump will be seen by Russia as a sign of weakness and create far more problems than it solves,” he said in a tweet.

House Speaker Paul Ryan said there is “no question” that Russia interfered in the U.S. election.

“The president must appreciate that Russia is not our ally,” he said. “There is no moral equivalence between the United States and Russia, which remains hostile to our most basic values and ideals.”

Trump blamed both the U.S. and Russia for the poor state of relations rather than singling out the Kremlin for criticism. “I do feel that we have both made some mistakes,” he said.

He did not condemn Russia over its illegal annexation of Crimea or its continuing support of separatists in eastern Ukraine. Instead Trump criticized the special counsel investigation, saying, “It has had a negative impact upon the relationship of the two largest nuclear powers in the world.”

Before his meeting with Putin, Trump blamed “many years of U.S. foolishness and stupidity” for the damaged relations. Nebraska senator Ben Sasse criticized that position.

“This is bizarre and flat-out wrong,” he said. “The United States is not to blame. When the president plays these moral equivalence games, he gives Putin a propaganda win he desperately needs.”

Trump on Monday also again denied colluding with the Kremlin, an accusation Putin also described as “utter nonsense.” The Russian leader later said he wanted Trump to win “because he talked about bringing the U.S.-Russia relationship back to normal.”

Trump has often expressed a desire to improve relations and find areas of cooperation. “Our relationship has never been worse than it is now,” he said Monday. “However, that changed as of about four hours ago. I really believe that.”

Florida senator Marco Rubio rejected the idea that Putin wants to improve relations with America.