Stanton announced his bid for Congressional District 9 in October to run for the seat Democratic Congresswoman Kyrsten Sinema will vacate to run for U.S. Senate, but he's stayed quiet about his resignation plans until now.
State law requires elected officials to step down from their positions before turning in election petitions for a different office. Stanton's petitions are due May 30.
Stanton, a Democrat, served two terms as a councilman in Phoenix District 6 before he was elected mayor for the first time in 2011.
