Utah Sen. Mitt Romney said Friday that he’s not sure if he will endorse President Donald Trump for a second term and that he may not throw his weight behind anyone during the 2020 campaign.

“I don’t think endorsements are worth a thimble of spit,” the Republican former presidential candidate told reporters during an annual gathering of political leaders, wealthy donors and powerful businesspeople in the Utah ski-resort town of Park City. “I wouldn’t be surprised if I stay out of the endorsements.”

Romney wrote in the name of his wife, Ann, on his 2016 ballot, saying, “I still think she’s doing a fine job.”

The senator repeated his view that Trump will likely win re-election in 2020 as an incumbent presiding over a strong economy, though “it’s not a sure thing.”