Mitt Romney was the only Republican to vote to convict Donald Trump at the conclusion of the president's impeachment trial, but the Utah senator was once a top choice for the president's Secretary of State, even after he called the then-nominee a misogynist fraud who would endanger the country's safety.

Four years before he cast a guilty vote on the abuse of power charge against the president, the former Massachusetts governor warned Republicans about Mr Trump's rise to power. Months later, they were pictured together, smiling at a dinner to discuss Mr Romney's prospects as a potential cabinet member.

Their public statements condemning the more-moderate senator and volatile president have concealed their necessary working relationship for the sake of party unity.

But that relationship seemed to fracture when the former leader of the Republican party demanded to hear witnesses in the president's trial, then told the Senate that he's guilty of a "flagrant assault on our electoral rights, our national security, and our fundamental values". Mr Romney voted with other senate Republicans to declare the president "not guilty" on his obstruction of Congress charge. At the end of the trial, both men belong to the same party facing a pivotal election in November.

March 2016: 'Donald Trump is a phoney, a fraud'

The former governor of Massachusetts and one-time Republican presidential nominee lost to incumbent Barack Obama in the 2012 election.

As Mr Trump began to shape into the presumptive nominee in 2016, Mr Romney said Republicans were in danger of selecting "one of the dumbest and worst candidates in the history of the Republican party". Days later, he called him a "con man" and a "fake" in a speech to Utah University's Hinckley Institute.

"If we Republicans chose Donald Trump as our nominee, the prospects for a safe and prosperous future are greatly diminished," he said in his remarks. "Donald Trump is a phoney, a fraud. His promises are as worthless as a degree from Trump University."

He demanded to see the future president's tax returns, called him a misogynist and criticised his "absurd third-grade antics".

Mr Trump fired back a few days later at a rally in Maine: "You can see how loyal he is. He was begging for my endorsement. I could have said, 'Mitt, drop to your knees.' He would have dropped to his knees."

October 2016: 'Hitting on married women? Condoning assault?'

With the election just weeks away, a 2005 tape from the set Access Hollywood was released, in which Mr Trump can be heard boasting about assaulting women: "I don't even wait. And when you're a star, they let you do it. You can do anything. ... Grab them by the p****. You can do anything."

On Twitter, Mr Romney attacked the nominee: "Hitting on married women? Condoning assault? Such vile degradations demean our wives and daughters and corrupt America's face to the world."

November 2016: 'Very nice!'

Following his election, the president wrote on Twitter that Mr Romney had called congratulate the president-elect on his win. "Very nice!"

Mr Romney wrote on Twitter: "Best wishes for our duly elected president: May his victory speech be his guide and preserving the Republic his aim."

Then, in an apparent about-face, the two were photographed in the middle of a four-course dinner at swanky restaurant Jean-Georges in New York, where the president-elect was courting Mr Romney for as a potential head of his administration's State Department.

Photographed leaving the restaurant, Mr Romney smiled as he told reporters he had a "wonderful evening" and said he was "impressed with the remarks he made on his victory night".

He said Mr Trump "continues with a message of inclusion and bringing people together" and has "increasing hope" for his administration.

The pair also met at Mr Trump's golf club in New Jersey, where the job was also reportedly discussed. Mr Romney told reporters that they talked "in regards to the various theatres of the world of interest to the United States, of real significance".

Days later, the president's chief adviser Kellyanne Conway poured water over their budding relationship, telling NBC's Meet the Press that "people feel betrayed to think that Governor Romney, who went out of his way to question the character and the intellect and the integrity of Donald Trump, now our president-elect, would be given the most significant cabinet post of all."

But the president-elect said Mr Romney was still in the running to run the State Department, telling the Today Show in his first interview after the election that he was "able to put this stuff behind us".

February 2018: 'Thank you, Mr President, for the support'

After his move to Utah, Mr Romney campaigned to fill a US Senate seat previously held by Orrin Hatch. The president endorsed him.

"He will make a great Senator and worthy successor to [Mr Hatch], and has my full support and endorsement!" the president wrote on Twitter.

Mr Romney replied, saying: "Thank you Mr. President for the support. I hope that over the course of the campaign I also earn the support and endorsement of the people of Utah."

In July 2019, Mr Romney appeared to defend the president, failing to answer whether he believed Mr Trump's Twitter post telling four congresswomen of colour to go back to their countries of origin was racist: "I certainly feel a number of these new members of Congress have views that are not consistent with my experience and not consistent with building a strong America."

October 2019: 'Pompous ass'

As a Congressional investigation into the president's dealings with Ukraine began to take shape, Mr Trump railed against his impending impeachment, suggesting that Ukraine and China investigate Joe Biden, deflecting from the likely charges against him and claiming his political opponent should be the target.

Mr Romney called the president's comments "wrong and appalling".

He said: "When the only American citizen President Trump singles out for China's investigation is his political opponent in the midst of the Democratic nomination process, it strains credulity to suggest that it is anything other than politically motivated."