Arizona Republican Senator Jeff Flake has decided not to run for re-election in 2018. He told The Arizona Republic he doesn’t think there is a place for him in the Senate:

He told The Arizona Republic ahead of his announcement that he has become convinced “there may not be a place for a Republican like me in the current Republican climate or the current Republican Party.”

Flake said he has not “soured on the Senate” and loves the institution, but that as a traditional, libertarian-leaning conservative Republican he is out of step with today’s Trump-dominated GOP.

“This spell will pass, but not by next year,” Flake said.

Among Republican primary voters, there’s overwhelming support for Trump’s positions and “behavior,” Flake said, and one of their top concerns is whether a candidate is with the president or against him. While Flake said he is with Trump on some issues, on other issues he is not. And Trump definitely views him as a foe, having denounced Flake publicly and called him “toxic” on Twitter.

“Here’s the bottom line: The path that I would have to travel to get the Republican nomination is a path I’m not willing to take, and that I can’t in good conscience take,” Flake told The Republic in a telephone interview. “It would require me to believe in positions I don’t hold on such issues as trade and immigration and it would require me to condone behavior that I cannot condone.”

He made these remarks on the Senate floor:

Flake and President Donald Trump has fought against each other since Trump came up as a possible presidential candidate in 2015. The Arizona Republic noted that Flake “refused to endorse or vote for Trump” and criticized Trump’s platforms during the presidential race.

He even took aim at Trump in his book:

Flake further antagonized Trump and the president’s supporters this summer by publishing a book, “Conscience of a Conservative: A Rejection of Destructive Politics and a Return to Principle,” that took the Republican Party to task for embracing protectionism, nationalism and other tenets of “Trumpism” at the expense of traditional Goldwater-Reagan GOP values.

Flake won the Senate seat in 2012, but served in the House since 2001:

Something of a political maverick, he routinely angered fellow Republicans by highlighting their spending of taxpayer money on parochial priorities.

While in the House, Flake’s office ridiculed questionable pork projects with a series of “Egregious Earmark of the Week” news releases that usually included corny jokes and bad puns. In 2006, Flake was profiled by CBS’ “60 Minutes” in a flattering segment that compared him to the principled Jimmy Stewart character in the classic 1939 movie “Mr. Smith Goes to Washington.” His reform efforts are credited with helping lead to an earmark moratorium on Capitol Hill.

“If I’m remembered as the guy who killed earmarks, that’s a great thing,” Flake told The Republic in 2012.

Flake took up other fights during his years on Capitol Hill.

Flake was a free-trader who believed that the economic embargo against Cuba, which dated to President John F. Kennedy’s administration and was part of the U.S. effort to stop dictator Fidel Castro’s brand of communism from spreading to other countries in the region, had long ago outlived its usefulness. Flake worked for years to ease travel restrictions to Cuba, usually siding with Democrats on the issue and, early in the 2000s, drawing the ire of President George W. Bush’s administration and House GOP leaders. He found an ally on the Cuba issue in President Barack Obama.