Sen. Jeff Flake (R–Ariz.), who earlier this year condemned Donald Trump for tarring his political opponents as traitors, stopped just short of applying that label to the president today.

Flake’s comments came three days after Trump made controversial remarks at a joint press conference with Russian President Vladimir Putin. Trump told the world he accepted Putin’s claim that the Russian government did not interfere in the 2016 U.S. presidential election. After that position provoked criticism from across the political spectrum, Trump claimed on Tuesday that he misspoke and believes Russia did interfere in the election.

Speaking from the Senate floor today, Flake slammed Trump for initially rejecting the findings of national intelligence officials that Russia meddled in the election. “The findings of our intelligence community regarding the Russian aggression are not matters of opinion, no matter how powerful and strong Putin’s denial,” Flake said. “To reject these findings and to reject the excruciating specific indictment against the 12 named Russian operatives in deference to the word of a KGB apparatchik is an act of will on the part of the president, and that choice leaves us contemplating the dark mystery, ‘Why did he do that? What would compel our president to do such a thing?'”