Tensions among Republicans about President Donald Trump have boiled over as two senators accused Trump of debasing US politics and the country's standing abroad, a rebellion that could portend trouble for his legislative agenda.
The extraordinary public criticism of the president from Jeff Flake and Bob Corker further strained what had already been a fraught relationship between Trump and fellow Republicans as they try to enact tax reform and other policy items.
In an emotional speech on the Senate floor, Flake repeatedly targeted Trump's style of governing, saying American politics had become "inured" to "reckless, outrageous and undignified" behaviour from the White House.
"The instinct to scapegoat and belittle threatens to turn us into a fearful, backward-looking people," said the Arizona lawmaker, who announced he would not run for re-election next year.
"I will not be complicit or silent," Flake said.
Trump, via Twitter, has been unrelenting in his criticism of Corker and Flake, accusing them of supporting Democratic priorities, and using sometimes slashing language, such as his dismissal of Corker as "liddle Bob Corker".
By announcing he will be leaving when his term ends in early 2019, Flake effectively freed himself up to speak his mind, without having one eye on voter reactions in his home state.
Corker, who has also said he is not running for re-election in Tennessee, accused Trump of telling lies that could be easily proven wrong and wilfully damaging the country's standing in the world, eviscerating the president with comments that stirred deepening divisions in the Republican Party.
"You would think he would aspire to be the president of the United States and act like a president of the United States, but that's not going to be the case apparently," Corker told reporters. "I've seen no evolution in an upward way. In fact, I would say, he's almost devolved."
Trump has also provoked the ire of another respected senior Republican, Senator John McCain, whose war record he mocked during last year's campaign.
Last week, former Republican President George W Bush, who has kept a low profile since leaving office in January 2009, took a thinly veiled swipe at Trump in a speech in which he decried "bullying and prejudice" and denounced anti-immigrant sentiment.
