PHOENIX — Democrat Gabrielle Giffords’ resignation creates a political vacuum in southern Arizona’s 8th Congressional District — a vacuum that an endorsement by Giffords could help fill.

U.S. Rep. Gabrielle Giffords' decision to resign from Congress has set up a political free-for-all in her competitive southeastern Arizona district. Here are some potential candidates who may vie for the vacant seat: Top row, from left: Sen. Frank Antenori, R-Tucson; Sen. Paula Aboud, D-Tucson; Republican Jesse Kelly; Rep. Jonathan Paton, R-Tucson. Bottom row, from left: Rep. Steve Farley, D-Tucson; Giffords' husband Mark Kelly; sports broadcaster Dave Sitton; and Rep. Matt Heinz, D-Tucson. AP Photo

As potential replacements jockey for position in a special election, a question is whether Giffords will make an endorsement that would carry unusual heft.

That’s due to timing and the circumstances of Giffords’ departure. She has resigned from Congress, saying she needs to concentrate on her recovery from the head wound she suffered a year ago in a Tucson shooting rampage.

Timing is a factor because an endorsement would give the recipient a boost over potential rivals in what will be a quick-paced contest.

And the circumstances of Giffords’ departure — and her favorable public image — could create a goodwill or sympathy factor that rubs off on an endorsement recipient.

“If Gabby were to endorse someone for that seat, I think that there would be a lot of people say ‘Ah, this might give us a person that would provide us the same kind of representation that Gaby provided to us, that willingness to work across the aisle, to listen to our concerns, to be available to us,’” said state Sen. Linda Lopez, D-Tucson.

Gov. Jan Brewer on Friday chose April 17 for the special primary election and June 12 for the general election.

Endorsements normally don’t mean all that much, serving typically mainly to energize the campaigns of the recipient and to antagonize supporters of rival candidates, said Stan Barnes, a Republican lobbyist and former legislator. However, “Gabby’s would mean more than most.”

A Giffords announcement would be political gold for the beneficiary because of Giffords’ favorable image, said Bruce Merrill, an Arizona State University political science professor emeritus and a longtime pollster.

“That person will have a strong probability of winning. It would have far more significance than any (other) election,” Merrill said.

Jeff Rogers, Democratic Party chairman for Pima County, said party leaders have discussed the possibility of a Giffords endorsement. And Giffords fundraiser Joan Cauthorn said names were discussed during a recent meeting of Giffords supporters.

But so far there’s no word of a decision by Giffords one way or the other.

Giffords’ former campaign manager and her former campaign chairman, Rodd McLeod and Michael McNulty respectively, declined to comment on the possibility of an endorsement.

Democrats prominently mentioned in speculation about possible candidates include state Sen. Paula Aboud, state Reps. Matt Heinz and Steve Farley and pecan farmer Nan Walden, a former senior staffer to two U.S. senators.

None have formally announced candidacies, but Farley said his own political plans hinge to a degree on whether Giffords endorses him.

Farley said for now he’s sticking to his plan to run for the state Senate and that he’ll support anybody Giffords endorses in the congressional race.

However, “if it’s me, I’d step in and run,” Farley said. “That person is going to have an endorsement as having been chosen to carry out her legacy.

Meanwhile, the Republican field has already started to assemble. State Sen. Frank Antenori announced his candidacy Friday. Other Republicans expected to run include 2010 Republican nominee Jesse Kelly and sports announcer Dave Sitton.

Barbara Norrander, a University of Arizona political science professor who studies elections and political parties, said a Giffords endorsee likely would be favorably viewed by many voters as someone in sync with the former congresswoman.

There’s likely no downside to being endorsed by Giffords, but the sooner the better for the recipient so he or she can take the most advantage of it in assembling campaign organization and raising money, Norrander said.

Rogers, the party’s Pima County chairman, says he’s suggested that Giffords endorse Ron Barber, a Giffords congressional staffer and a survivor of the 2011 shooting, to run in only in the special election.

That would allow Barber to go to Washington to represent the district for six months while candidates running for a two-year term battle it out in the fall election, Rogers said.

“He could just go back and concentrate on doing the people’s work,” Rogers said.