Some of that tension appeared to wane after reports that Trump was considering Romney to be his secretary of state, but the president has reportedly remained wary of Romney's allegiances and lobbied heavily for Hatch to run for re-election rather than retire.
Romney immediately thanked the president on Twitter for his endorsement.
Neverthelesss, it seems Senate Majority Leader Mitch McConnell was correct when he said on Saturday that he "can't imagine" Trump would not support Romney's candidacy. Romney acknowledged that to the AP, saying, "I can fight for the people of Utah and do more for Utah than the average junior senator might be able to accomplish".
Relations between the Senate hopeful and the President have not always been so cheery.
Romney is aiming to replace 83-year-old Sen.
"Donald Trump is a phony, a fraud", Mr. Romney said in a speech in Salt Lake City.
Hours after making his campaign announcement early Friday, Romney filed paperwork with Utah's elections office allowing him to start collecting the signatures of 28,000 registered Republicans to earn a spot on a June primary ballot.
Romney said Trump was playing Americans "for suckers" and predicted that he would never release his tax returns as promised because "He has too much to hide".
In a famously scathing speech delivered in the midst of the presidential campaign in March 2016, the former MA governor who ran unsuccessfully against President Obama in 2012 called Trump a "con man" whose promises are "as worthless as a degree from Trump University".
Romney's designs on the Utah seat were known well before he announced last week. He's a Brigham Young University graduate who went on to become the first Mormon presidential nominee of a major political party.
Amid intense conservative opposition to the national law, however, Romney distanced himself during his 2012 campaign from his MA accomplishments, arguing that he had pursued a state solution that wasn't appropriate at the federal level.