Arizonans head to the polls Tuesday to vote on who will temporarily replace former Rep. Gabrielle Giffords.

Whoever wins the Congressional District 8 special election will finish out Giffords's term. The congresswoman suffered severe brain trauma Jan. 8, 2011 after being shot in the head while holding a public event near Tucson.

Giffords stepped down from her seat in an emotional goodbye earlier this year. She told her peers that she wanted to focus on her recovery.

On Tuesday, voters will choose between four Republicans: Frank Antenori, Jesse Kelly, Martha McSally, and Dave Sitton.

The winner will step into a hotly contested swing district and go on to challenge the only Democrat, Ron Barber, in the special election.

Democrats hope Barber will increase their chances of keeping the seat. Barber served as Giffords' former district director and was one of the 13 injured at the shooting that critically wounded the three-term lawmaker.

Both sides predict a tight race. Local Republicans say that multiple candidates may be good for voters but it could ultimately hurt the race for campaign dollars.

"As a candidate, it is not that good because you have to take now some assets from your campaign war chest to gain position on the ballot and then against the Democratic candidate,"

Matt Creegan, with the Cochise Country Republican Committee, said.

The seat is so contested that it's attracting money and effort from Republicans and Democrats at the national level.

Mark Rom, an associate professor of government at Georgetown University, said he expects the winning party to proclaim the victory as a prediction for the future.

"The party that loses will say, 'Eh, it was just a special election," he said.

Either way, the victory will be short-lived. Voters return to the polls in November to re-elect a permanent representative for the seat.