Flake's bombshell announcement today that he would not seek reelection next year is rocking the state's political landscape.

Flake took time on the Senate floor today to explain his decision, saying that the coarseness of President Donald Trump drove his decision. Talking Points Memo summarizes:

“I have children and grandchildren to answer to. And so, Mr. President, I will not be complicit or silent,” Flake said in a speech that centered around the degradation of political civility in the age of Trump.

He criticized the “coarseness of our leadership” and the “regular and casual undermining of our democratic norms and ideals.”

“When the next generation asks us, ‘Why didn’t you do something? Why didn’t you speak up?’ What are we going to say? Mr. President, I rise today to say, enough,” Flake said. “We have fooled ourselves long enough that a pivot to governing is right around the corner, a return to civility and stability right behind it. We know better than that. By now we all know better than that.”

“We must stop pretending that the conduct of some in our executive branch are normal. They are not normal. Reckless, outrageous and undignified behavior has been excused as ‘telling it like it is’ when it is actually just reckless, outrageous, and undignified,” Flake continued. “And when such behavior emanates from the top of our government, it is something else. It is dangerous to a democracy.”

I suspect Flake would not have made this move if he hadn't seen polling numbers that showed his support collapsing among Republicans in Arizona. That problem been building for awhile, but his feuds with Trump have definitely accelerated his decline—and his decision to write a book hammering away at Trump surely didn't help things.

I don't agree with many of Flake's policies (other than his push to solve the nation's immigration problems with the Gang of Eight back in 2013), but I do believe he is a fundamentally decent guy who wants to reverse the rot within his party. But he's spitting into the wind. The GOP is moving in a sharply different direction where primary voters celebrate what Trump represents.

So what happens next? I'm guessing there's a rush among Republicans to jump for the open seat and Flake challenger Kelli Ward will now face a more crowded and difficult path to the GOP nomination. And not to be morbid, as we wish him the best with his battle against brain cancer, but there is also a possibility that John McCain won't be able to finish his term, which could put both of Arizona's U.S. Senate seats in play next year.