In the race for Southern Arizona's eighth congressional seat, it is all immigration, all the time.
By Rene Gutel
Mr Graf's Minutemen are already building their own fence
The sprawling district, which includes part of the city of Tucson, borders Mexico for 80 miles (129km) and border security is a focal point in the campaigns.
On the Republican side is Randy Graf, 47, a hardline conservative who has broken rank with President George W Bush and other Republican leaders on immigration.
A former professional golfer and state lawmaker, Mr Graf advocates a tough and controversial approach to US border policy.
He is facing Gabrielle Giffords, 36, the youngest woman ever elected to the Arizona Senate.
Ms Giffords, despite being a Democrat, stands with the president and Arizona Senator John McCain in support of comprehensive immigration reform, including the creation of a guest-worker programme.
This race is being closely watched because it is one of only a couple of dozen around the country which could determine whether Democrats take control of the House on 7 November.
Analysts also say a Graf win could signal a major shift in immigration politics at the national level.
The airwaves here are inundated with campaign commercials. In a radio spot for Randy Graf, a female voice intones that America's borders are "an open door" for "drug dealers, criminals, even terrorists".
Mr Graf wants the entire Mexican border fenced off. He says the number of border patrol agents should be quadrupled or quintupled, and that social services should be denied to undocumented citizens.
"Very simply, we need to stop illegal immigration," he says.
"That includes interior enforcement and trying to dry up the job market, the benefit structure that illegal aliens take advantage of.
"If illegal aliens can't get a job, can't get benefits and local law enforcement doesn't help, then I believe the vast majority of them will go home, apply for a legal temporary work visa and fill the jobs they're filling today."
Mr Graf is a founding member of the civilian border patrol group, the Minutemen, and his tough talk goes over well in parts of rural Arizona and in retirement communities like the Sun City Vistoso Adult Community outside Tucson.
"I'm going to vote for Graf," says retiree Stick Jacobs, who came to hear Mr Graf speak at a candidate forum.
"He's anything but extreme. I find his views moderate. I'm for sealing the border first, before we do
anything else. After that, fine, let's talk about citizenship down the road, but first of all seal the border."
The congressional seat is up for grabs because the incumbent, moderate Republican Jim Kolbe, is retiring after 22 years in Washington.
Ms Giffords calls herself a moderate Democrat and says she is better suited than her conservative opponent to represent the district, whether the issue is the war in Iraq, health care or immigration.
"We need a lot more than enforcement," Ms Giffords says.
"Yes, we need security, but we need a guest-worker programme. We also need to get tough on employers who are illegally hiring people.
"My opponent talks about building a wall across the entire expanse of the US-Mexico border, about deporting 12 to 14 million people. His approach is unrealistic."
Mr Graf paints Ms Giffords as too liberal but she insists her support for a path to citizenship for undocumented workers already here is not the same as granting them blanket amnesty.
She is consistently ahead in public opinion polls.
The district includes part of Tucson and leans moderate, which helps her attract voters like 21-year-old student Justin Goodenkauf.
He is a Republican voting for Giffords because he says Randy Graf's border policies do not focus enough on prevention.
"It's more than just build a big fence, more border security, more border patrol," Mr Goodenkauf says.
"Giffords' plan actually goes further than that, and that's what I'm looking for."
All eyes on Arizona
Mr Graf is widely considered the underdog in the race.
He did, however, turn heads earlier this month when he secured John McCain's endorsement.
The Republican senator applauded Mr Graf's record on reducing taxes and supporting the military but made no mention of Mr Graf's immigration positions, which Mr McCain opposes.
Still, Mr Graf called the endorsement a "turning-point" in his campaign.
Jim Geraghty, a contributing editor at the conservative magazine National Review, has been keeping an eye on the race.
Mr Geraghty says if Mr Graf wins in November, it will be a political earthquake felt all the way to Washington.
"I think a lot of politicians across the country are going to say 'Wow, this issue really does have salience and it really can be enough to really propel an insurgent candidate'.
"I think everybody, the Republican side, the Democratic side, are going to look at it and say, 'Am I tough enough on this issue?'"