Washington • Mitt Romney has chosen a longtime aide, who is also the treasurer of President Donald Trump’s campaign, to head up financial accounting for his Senate bid in Utah, a new filing with the Federal Election Commission shows.

Romney, who had been sharply critical of Trump but has now welcomed his endorsement, tapped Brad Crate, based in Massachusetts, to serve as treasurer of his Utah campaign.

During the 2016 election, Crate was the treasurer of the Trump Victory Fund and the Trump Make America Great Again Committee, joint fundraising committees that backed Trump. He is the treasurer of Trump’s re-election campaign.

Crate has worked for Romney since he first ran for governor of Massachusetts in 2002 and worked in his gubernatorial office after Romney won. He subsequently was the chief financial officer of Romney’s 2008 and 2012 presidential campaigns. Crate’s brother, Darrell, was Romney’s treasurer during those bids as well.

Romney’s filing with the FEC is the first step in the federal campaign. It only lists basic details and does not cover how much the campaign has raised or spent thus far.

Romney’s campaign did not respond to a request for comment.

Trump and Romney have had a back-and-forth relationship over the years. Trump endorsed Romney in his 2012 presidential run, but during the Republican primaries in 2016, as Trump was edging close to winning the nomination, Romney excoriated him, calling Trump a “phony, a fraud” and had been critical on social media of Trump’s actions.

But after Trump won the presidency, Romney sat down for dinner with him as he eyed the job of secretary of state, a position that Trump gave to former ExxonMobile CEO Rex Tillerson.

When Sen. Orrin Hatch said he wouldn’t run again for the Senate seat from Utah, Trump called Romney to encourage him to run, a senior White House official told The Salt Lake Tribune.

On Tuesday, Trump tweeted that Romney “will make a great senator and worthy successor” to Hatch and that he has his “full support an d endorsement!”