Democrats face a delicate situation in the fall if their nominee to finish former Rep. Gabrielle Giffords's (D-Ariz.) term wins a special election in the summer.

When Ron BarberRonald (Ron) Sylvester BarberPrinciples and actions mean more than Jeff Flake’s words Giffords to lawmakers avoiding town halls: 'Have some courage' Ten House seats Dems hope Trump will tilt MORE announced in February he would run in the June special election to finish Giffords’s term, he said he hadn’t decided whether he would also run for a full term starting in 2013.

Democrats cleared the primary field for Barber, a longtime Giffords staffer who was hit twice in the January 2010 shooting spree that killed six people, critically injured Giffords and led to her resignation one year later. But four Democratic candidates said they still planned to run in the regular election in the fall for a full term.

Then Barber announced on Monday he had decided to pursue a full term, leading to a potential primary showdown if he wins the special election.

One of the Democrats — whose campaign was being managed by another former Giffords aide — dropped out. But two others said they were staying in: Arizona state Sen. Paula Aboud and state Rep. Matt Heinz. A fourth Democrat has not made her plans known.

"I'm supporting Ron to replace Gabby for the rest of the term," Aboud said last week in a telephone interview. "But I'm moving forward, and I am focused on the new district in the fall."

The lingering question for Aboud and Heinz is whether their plans for running in the fall now hinge on Barber being defeated. Neither candidate has said whether he or she would move forward with a primary challenge to Barber if he is elected in June.

“Clearly folks in his own party don’t have much confidence he’s going to win this special election. Otherwise, they wouldn’t still be running,” said National Republican Congressional Committee spokesman Daniel Scarpitano.

Republicans have a small advantage in the district in the special election and could feasibly flip the seat, helping them stave off a coup in Washington by Democrats, who need to flip about 25 seats to regain control of the majority in November.

But the regular election for the full term is being conducted under new congressional lines that make the seat slightly more favorable for Democrats.

Despite the good will afforded by southern Arizona voters to Barber — who has been endorsed by Giffords, her husband and even local GOP officials — his success in the special election is no sure bet. Barber will need crossover votes from Republicans to win, and at least four Republicans are running in the primary, including Jesse Kelly, who came within two points of defeating Giffords in 2010.

“Republicans don’t vote for someone because they got shot,” said one GOP source in Arizona. “They just don’t.”

Many Arizona Democrats expected Barber would serve as a placeholder for Giffords and then relinquish the seat. His decision to the contrary prompted questions about why he hadn't made his intentions clear from the beginning.

"Some people might ask, 'Hey Ron, what took you so long?'" Barber said when he announced he would run for the full term. "I don’t rush into things, but once I make a decision, I stick with it for the long haul."

Others speculated that he had stayed silent about his plans for the full term so that the other Democrats would bow out of the special election, expecting they would have a clear shot at the seat in the fall.

That way, by the time Barber announced a run for the full term, he would already have the air of the established Democratic pick, and pressure would mount for the others to call it quits.

The Democratic Congressional Campaign Committee (DCCC) stays officially neutral in primaries for open seats, but supports incumbent members when they run for reelection and are challenged in the Democratic primary. The DCCC said if Barber is elected in the special election, the committee will support him in the primary for the full term as well.

“Let’s be real. Yes, of course there will be some pressure on them to drop out,” said David Waid, a former chairman of the Arizona Democratic Party. “Including from the DCCC.”

Barber will also have the glow of a recent electoral victory, established name recognition and an incumbent's fundraising advantage, making it an uphill battle for Democrats to oust him in the primary.

But he will also have the disadvantage of facing a general election, a primary election and then another general election — all in the course of less than six months.

“In this scenario, you have a person who runs to the center, then runs to the left, then runs to the center, because all three of these are competitive races,” Waid said. “It’s a tough role to fill.”

Barber’s campaign declined to comment for this story.