Sen. Jeff Flake (R-AZ) announced his decision to retire from the Senate rather than seek re-election in 2018, citing the new tone and political values that President Donald Trump brought to Washington, DC, as the reason.

“When the next generation asks us, ‘Why didn’t you do something? Why didn’t you speak up?’ What are we going to say?” Flake said sorrowfully as he stood up in the Senate for his announcement. “Mr. President, I rise today to say, enough.”

Flake said that he no longer could serve as a conservative in a party that no longer valued free trade or immigration.

“It is clear at this moment that a traditional conservative, who believes in limited government and free markets, devoted to free trade, pro-immigration, has a narrower and narrower path to nomination in the Republican party,” Flake said, his voice trembling with emotion.

He added that under Trump, American world leadership is endangered and the long-standing principles of Democracy have been shattered.

“I rise today with no small measure of regret,” he said. “Regret because of the state of our disunion, regret because of the disrepair and destructiveness of our politics.”

Flake spoke repeatedly about his principles, complaining that they did not align with Trump’s agenda. But his biggest complaint was that Trump had coarsened the political dialogue.

“It is time for our complicity and our accommodation of the unacceptable to end,” he said, criticizing the phrase “the new normal” to describe Trump’s behavior in Washington, DC.

He said that the ongoing destruction of established norms in the Senate was “appalling.”

“If we simply become inured to this condition, thinking that this is just politics as usual, then heaven help us,” he said.