Flake’s Blistering Attack on Trump Is the Latest Crack in GOP Unity, by Laura Litvan.

Republican Senator Jeff Flake of Arizona announced he won’t seek re-election and then delivered a blistering attack on Donald Trump on the Senate floor, the second GOP senator to publicly excoriate the president on the day the party wanted to put a proposed tax overhaul at the forefront.

“Outrageous and undignified behavior has been excused as telling it like it is when it is actually reckless, outrageous, and undignified,” Flake said Tuesday, without mentioning Trump’s name. “When such behavior emanates from the top of our government, it is something else. It is dangerous to democracy.”

Flake’s remarks followed a series of television interviews in which Tennessee Senator Bob Corker denounced Trump, followed by angry retorts from the president. …

The highly unusual back-and-forth also lays bare a widening split within the Republican Party and Trump’s most loyal backers. The president’s former strategist, Steve Bannon, is backing challengers to incumbent Republican senators, including Flake, and aims to depose Majority Leader Mitch McConnell. He’s already scored one victory in an Alabama primary by backing Roy Moore, the former judge who’s been accused of bigotry, in a successful runoff election against Senator Luther Strange, who had support from Trump and McConnell. …

Corker had previously announced he wouldn’t seek a third term. Once a solid Trump backer, Corker on Tuesday said he wouldn’t do so again. …

Great America Alliance, a group aligned with Bannon, said in a statement that Flake’s decision not to run for re-election “should serve as another warning shot to the failed Republican establishment that backed Flake and others like them that their time is up.”