Flake, an establishment conservative who has served in the Senate since 2013 and has been an outspoken critic of Trump-era politics...
Senator Jeff Flake assailed Trump in a bombshell 17-minute floor speech that sounded like a distress call warning of a "reckless presidency," just minutes after Trump made a rare foray to Congress to dine with Republican senators.
Flake's surprise announcement came hours after a Republican colleague, Senator Bob Corker of Tennessee, reignited his war of words with Trump, calling him an "utterly untruthful" leader who "debases" the nation.
The extraordinary developments on Capitol Hill only deepened the tensions between Trump and his party, some of whose establishment members have grown increasingly concerned about his coarse and combative style of governing.
Flake, an establishment conservative who has served in the Senate since 2013 and has been an outspoken critic of Trump-era politics, displayed visible emotion as he announced he would not seek re-election next year.
"The personal attacks, the threats against principles, freedoms and institutions, the flagrant disregard for truth and decency... none of these appalling features of our current politics should ever be regarded as normal," said the 54-year-old Arizona Republican.
"We must stop pretending that the degradation of politics and the conduct of some in our executive branch are normal," Flake warned.
"Reckless, outrageous and undignified behavior is excused as telling it like it is, when it's actually just reckless, outrageous and undignified."
Flake blasted Trump for his unfettered tweeting, and attacked fellow Republicans for keeping quiet as "the alliances and agreements that ensure the stability of the entire world are routinely threatened by the level of thought that goes into 140 characters."
"Politics can make us silent when we should speak and silence can equal complicity," added the senator. "I will not be complicit or silent."
Tuesday was supposed to be a good day for the often-strained relations between Trump and his party.
The president attended the Senate Republican caucus lunch for the first time since his inauguration, to press for a unified front for passing a package of tax cuts before year's end.
But the unity unraveled before he even arrived.
The focus swerved instead to a brutal back-and-forth between Trump and Corker, the influential Senate Foreign Relations Committee chairman who has excoriated the president as dangerously impulsive and branded the White House an "adult day care center."
When Corker urged the president early Tuesday to stand clear of the tax debate and "leave it to the professionals" -- Trump rounded on him in a series of tweets, and the war of words was on.
"Bob Corker, who helped President O give us the bad Iran Deal & couldn't get elected dog catcher in Tennessee, is now fighting Tax Cuts," Trump tweeted.
"Same untruths from an utterly untruthful president," shot back Corker, who opposed the Iran nuclear deal because he believed it was too weak.
"I don't know why he lowers himself to such a low, low standard and debases our country in the way that he does, but he does," Corker -- who like Flake is not seeking re-election next year -- went on to tell reporters, voicing regret for supporting Trump's presidential bid.
In the past week, Trump has been harshly criticized by two high-profile Republicans: former president George W. Bush, who said "bigotry seems emboldened" in the Trump era, and Senator John McCain, a former war hero who issued a searing rebuke to Trump's ideas and politics.
Trump's feud with Corker has further exposed the president's tensions with some Republicans in Congress, where a major legislative victory this year has proved elusive.
Immediately after Flake's speech, McCain, the senior senator from their state of Arizona, praised him for his "honor" and "patriotism."
"I have seen Jeff Flake stand up for what he believes in, knowing full well that there would be a political price to pay," McCain said.
Trump has previously attacked Flake as "weak" and "ineffective," and has derided Corker's height while labeling him "incompetent."
White House spokeswoman Sarah Huckabee Sanders responded to their twin attacks on Trump by saying voters would likely not have supported either senator were they to have run again.
"I think that they were not likely to be re-elected, and I think that that shows that the support is more behind this president than it is those two individuals," she said.
Republicans and Democrats alike expressed their sadness about Flake's announced departure.
"Jeff Flake is good people," said Democratic Senator Brian Schatz.
"If he's not sufficiently Republican, I don't know what the modern Republican Party is."