FILE - Donald Trump greets Republican presidential candidate, former Massachusetts Gov. Mitt Romney, after announcing his endorsement of Romney during a news conference, Feb. 2, 2012, in Las Vegas. (AP Photo/Julie Jacobson, File)

FILE - Donald Trump speaks at a news conference in Las Vegas, Thursday, Feb. 2, 2012, to endorse Republican presidential candidate, former Massachusetts Gov. Mitt Romney, center, accompanied by Romney's wife Ann. (AP Photo/Gerald Herbert, File)

FILE - Mitt Romney smiles during a campaign event, June 20, 2018, in American Fork, Utah. (AP Photo/Rick Bowmer, File)