A contender to receive Gov. Doug Ducey’s appointment to serve as Arizona’s next senator was sharply critical of President Trump during the 2016 campaign.

Maricopa County Attorney Bill Montgomery is on Ducey’s list of possible appointees as he mulls who to choose to succeed Sen. Jon Kyl, R-Ariz., whom the governor appointed on an interim basis to replace Sen. John McCain after the iconic Republican died in office in August. But Montgomery, a Republican, could have a Trump problem in the way of critical tweets.

During the inaugural Republican presidential debate in August of 2015, Montgomery tweeted: “Trump unforced error #1: failing to commit to supporting Republican nominee. You’re fired!” About a month later, during the second debate, Montgomery tweeted: “Waiting for Donald Trump to take credit for inventing the Internet. Most interesting man in the world?”

“tired of the Trump show. You’re fired,” Montgomery said in yet another tweet.

Kyl is resigning his appointment on Dec. 31, and Ducey is looking for a Republican who would stand in a special election in 2020 to determine who will finish the final two years of the term McCain won in 2016. If successful, this appointee would have to turn around and run again, for a regular six-year term, in 2022.

It’s a tall order that will require near-constant campaigning and raising tens of millions of dollars.

The appointee could also face a competitive primary in 2020, and that race could be tough to win without Trump’s support. However, the president doesn’t appreciate critics, and can hold grudges against Republicans who opposed him in 2016. That could prove problematic for Montgomery, who during a press conference this week sidestepped questions about his interest in the Senate appointment.

“I’m the county attorney until I’m not the county attorney. I like this job,” Montgomery said. His office declined to comment on the past tweets critical of the president.

Outgoing Rep. Martha McSally, R-Ariz., who lost her Senate bid on Nov. 6, is in the running for Ducey’s selection, as is state Treasurer Eileen Klein and the governor’s former chief of staff, Kirk Adams.

