PHOENIX — Former Arizona sheriff Joe Arpaio has announced he plans to run for the U.S. Senate seat now held by Jeff Flake.

The 85-year-old Arpaio is a close ally of President Donald Trump and tweeted Tuesday he seeking the post “to support the agenda and policies of President Donald Trump in his mission to Make America Great Again.”

I am running for the U.S. Senate from the Great State of Arizona, for one unwavering reason: to support the agenda and policies of President Donald Trump in his mission to Make America Great Again. https://t.co/ANppBdDOtp — Sheriff Joe Arpaio (@RealSheriffJoe) January 9, 2018

Arpaio was spared a possible jail sentence last year when Trump pardoned his conviction for disobeying a judge’s order in an immigration case.

He flirted with the idea running for Arizona governor five times but decided against doing so each time.

Arpaio says in a fundraising email that he filed paperwork Tuesday for the Senate run.

Flake has been critical of Trump and announced last year that he would not seek another term.