Ron Barber hugs a friend at the end of an interfaith remembrance service at St. Augustine Cathedral Jan. 8 in Tucson. (Pat Shannahan/AP)

Barber was a longtime aide to the ex-congresswoman, and he was shot in the Tucson massacre that killed six people and wounded 13. Giffords, who was shot in the head, resigned in January to focus on her own recovery.

He had previously committed to running in the special election for Giffords’s 8th district seat, with the support of his old boss. Barber now plans to also run in November for what will become the 2nd district after remapping. The swing seat will become slightly more Democratic.

“I don’t rush into things, but once I make a decision, I stick with it for the long haul,” he said in a news release, explaining that he made up his mind over the weekend. “But don’t take my word for it. Ask my wife Nancy. We started dating in 1963.”

State Rep. Steve Farley (D) dropped out of the Democratic primary in response to Barber’s decision, saying he would run for state Senate instead.

Four Republicans are also vying for the seat. The primary is April 17; the general election is June 12.