Since Vice President Mike Pence led the Congress session that ceremonially confirmed his boss Donald Trump had lost the November election, relations between the two top Republicans have plummeted to an Arctic chill.
The men have not spoken after the president's supporters violently stormed the Capitol on Wednesday, according to the US media, which also reports that Pence intends to be at Biden's inauguration despite Trump saying he will skip it.
It is a stark rupture between the precedent-shattering Trump and his deputy who has been the president's most devoted foot soldier for the past four years.
"Vice President Pence, one of the most faithful guys to Donald Trump, is now Public Enemy Number One in Trump World," Republican lawmaker Adam Kinzinger said Sunday on ABC's "This Week."
In an angry speech outside the White House on Wednesday, Trump urged his supporters to march to the Capitol and demand that Pence, who as vice president led the joint session of Congress, must intervene to reverse the Republicans' election defeat.
Pence refused, and he was ultimately the one who announced to lawmakers Trump's and his loss to Joe Biden and Kamala Harris, the incoming vice president.
But before the certification was complete, a pro-Trump mob descended on the symbolic seat of American democracy in an attack that ended with five dead and international condemnation.
"Mike Pence didn't have the courage to do what should have been done to protect our Country and our Constitution," was the president's damning assessment on Twitter.
Wednesday's frenzied riots posed a clear danger to lawmakers, and to Pence himself -- who was hustled out of the chamber by Secret Service officers.
Some Trump supporters, furious over Pence's action, chanted that he should be hanged. Trump reportedly did not call to check whether his deputy was safe.
- Once the loyalest of all -
While Pence condemned the violence, the president released a video message that urged the rioters to be peaceful but then added: "We love you. You're very special."
The gap between the two men appeared to widen further when Trump learned that Pence would attend Biden's January 20 inauguration, in keeping with tradition.
The president -- who says the election was rigged -- has declined to attend, despite his claim following the Capitol riot that he wanted to ensure a "peaceful transition."
Adding to the tension, Pence has reportedly not ruled out backing efforts to invoke the 25th Amendment to oust Trump in his final days in office for being unfit to serve.
It is all very different from Pence's previously vocal and consistent support for Trump.
Trump called him "as solid as a rock," and ever-dutiful Pence took on a tough role during Covid-19, fronting up the White House taskforce as public anger grew over the government's floundering response to the pandemic.
Calm, disciplined and discreet, Pence, 61, was a surprise choice as Trump's vice president back in 2016, but he brought with him much-needed support from the Christian right, and he had stayed loyal through many storms.
A former Indiana governor, he is known to be keenly interested in a 2024 run for the White House.
It was always a tricky political challenge for Pence to try to use being Trump's deputy as a springboard for the top job. It remains unclear if he will emerge undamaged from Trump's chaotic and violent departure from the White House.