The former Republican US presidential candidate and incoming senator for Utah Mitt Romney has launched a scathing attack on Donald Trump, saying he has caused dismay around the world.
Writing in the Washington Post, he said Mr Trump had not “risen to the mantle” of the presidency.
Mr Romney has been fiercely critical of Mr Trump before but won his backing for his run in Utah.
There has been no response yet from the US president.
Just two days before Mr Romney is sworn-in, prompted some to speculate he was positioning himself as a challenger to Mr Trump securing the Republican presidential nomination.
In the article, Mr Romney praised many of Mr Trump’s policies, such his tax reforms and appointment of conservative judges, ones he said “mainstream Republicans have promoted for years”.
But he went on to say: “With the nation so divided, resentful and angry, presidential leadership in qualities of character is indispensable. And it is in this province where the incumbent’s shortfall has been most glaring.”
“The world is also watching,” he added. “Trump’s words and actions have caused dismay around the world.”
Mr Romney said he would support the president in policies he thought were in the best interests of Utah or the US but speak out against actions “that are divisive, racist, sexist, anti-immigrant, dishonest or destructive to democratic institutions”.