U. S. Senate candidate Mitt Romney addresses delegates at the Utah Republican Nominating Convention last month. (Leah Hogsten/The Salt Lake Tribune via AP)

Mitt Romney, whose rocky relationship with President Trump has become an issue as he seeks a Senate seat in Utah, has revealed his choice for commander in chief in the 2016 election: his wife, Ann.

Romney, the GOP’s 2012 presidential nominee, had previously said he wouldn’t vote for Trump, whom he called a “fraud” during the 2016 campaign, or for Democrat Hillary Clinton. But until Wednesday, the name he wrote in on his ballot remained a mystery.

“I wrote in the name of a person who I admire deeply, who I think would be an excellent president,” Romney told the Deseret News and KSL-TV editorial boards in response to a question. “I realized it wasn't going to go anywhere, but nonetheless felt that I was putting in a very solid name.”

Romney’s comments came as he campaigns in advance of a June 26 Republican primary in the race to replace retiring Sen. Orrin G. Hatch (R-Utah).

Last month, delegates at the Utah GOP’s state convention denied Romney their party’s nomination outright as Mike Kennedy, a three-term state representative who entered the race just weeks earlier, edged out the establishment favorite with 50.88 percent of the vote to 49.12 percent.

The close result secured ballot slots for Romney and Kennedy in the primary contest.

Kennedy has sought to make an issue of Romney’s past antipathy for Trump an issue in a primary that Romney, a former governor of Massachusetts, is heavily favored to win.

Kennedy, however, acknowledged after a debate with Romney on Tuesday that he wrote in Sen. Ted Cruz (R-Tex.) for president in 2016.

Since launching his bid, Romney has offered praise for many of Trump’s policies while still criticizing his character.

Earlier this week, Romney told NBC News that he would not consider Trump a role model for his grandchildren “on the basis of his personal style.”