Speaking to a rapt audience of other senators, the first-term Arizona lawmaker spelled out his frustration and disappointment in a floor speech before relaying the news that he would not be on the ballot in 2018.
"There are times we must risk our careers," Flake said. "Now is such a time.
Flake, who has criticized the path the Republican Party has taken under Trump, said the impulse "to threaten and scapegoat" could turn America and the GOP into a "fearful, backward-looking people" and a "fearful, backward-looking party." Flake didn't mention Trump by name, but his remarks were unmistakably aimed at the president and his administration.
Flake, a former House member, is a conservative who favors limited government and free markets has been known to work on bipartisan legislation. Most notably, he joined Democrats and Republicans on legislation aimed at finding a path to citizenship for the 11 million immigrants living in the United States illegally.