There were headline-grabbing mass shootings in Tucson, Ariz.; Aurora, Colo.; and Newtown, Conn. — and then there’s daily life in Chicago.

“It’s not that I’m insensitive,” said Rep. Mike Quigley, a Democrat representing downtown and northwest Chicago. “This kind of shocking, horrible situation is taking place in neighborhoods in the 2nd congressional District every weekend.”

As the nation laments the Dec. 14 massacre at an elementary school in Connecticut, 2nd District residents know the pain all too well. In the past two years, Chicago gun violence spiked on the city’s south and west sides.

Gun policy rarely plays a deciding role in an election — especially in a Democratic primary. But the issue looms large in the upcoming special election to replace ex-Rep. Jesse L. Jackson Jr. A confluence of local events placed gun policy in the spotlight here long before the tragedy at Sandy Hook Elementary School.

There’s the frequent gun violence: 319 public school students were shot in the 2011-2012 school year, according to the Chicago Police Department. Twenty-four of them died.

Then, earlier this month, the local Democratic bosses’ favorite candidate, state Sen. Donne Trotter, attempted to bring a gun onto a plane at Chicago O’Hare International Airport. Trotter said he didn’t realize the firearm was in his garment bag, but he must appear in court next month to contest the felony charge.

Just a few days later, on Dec. 11, a federal appeals court overturned the state’s restriction on carrying concealed weapons. It was the only statewide ban of its kind in the country.

Finally, there’s the large roster of Democrats seeking the seat, including two previously backed by the Illinois State Rifle Association. Given the unwieldy field, any one of the seven better-known candidates — including those two — could win the Feb. 26 primary.

“It’s going to make a difference in the Illinois delegation, certainly,” said Richard Pearson, ISRA’s executive director. “One 435th of a vote? We’ll take it.”

The primary victor will likely become a member of Congress from this heavily Democratic district. Jackson, a Democrat, represented the area for eight terms until he resigned in November amid a federal inquiry probing his alleged use of campaign funds for personal purchases.

The 2nd District includes mostly urban turf on the Chicago’s south side but stretches down along the Indiana border and includes rural Kankakee County. A diverse district invited a diverse field of candidates and an unpredictable race.

“I think that many people — and I would venture to say a majority of the people in that district — have some strong feelings about gun control,” Rep. Danny K. Davis, D-Ill., said in a recent phone interview. “The strong feeling that they have is we should minimize the presence of guns to the extent that we can in our environment.”

One of the race’s top contenders, former Rep. Debbie Halvorson, received support from the National Rifle Association and the ISRA in her previous bids in more conservative districts. Jackson used Halvorson’s affiliations with the NRA in a devastating television spot during their primary earlier this year.

Halvorson lost that bid by a massive margin, but the math is different this time, with at least five Democratic candidates from the inner city: Alderman Anthony Beale, Cook County Chief Administrative Officer Robin Kelly, former NFL linebacker Napoleon Harris, former Rep. Mel Reynolds and Trotter.

In an interview, Halvorson defended her position on gun control, noting “a criminal will always find a way to get a gun.” She said she “may” support an assault weapon ban but that all options should be “on the table.”

“I’m not going to change just because this is a primary with a lot of candidates,” she said. “I know where I stand. I’ve been doing this for 20 years.”

Another candidate, state Sen. Toi Hutchinson, represents the district’s southern end, including rural territory formerly represented by Halvorson in the Legislature. She’s also been backed by the ISRA.

Hutchinson did not respond to a request for an interview, but an aide said she’s always been a “strong advocate for hunting rights,” but she does support gun control policies such as a ban on assault weapons or high-capacity magazines.

If Halvorson’s and Hutchinson’s support from pro-gun groups is not an issue yet, it might be soon. On Tuesday, Kelly submitted an open letter to her opponents, asking them to sign on to five gun control initiatives. One of those initiatives asked her competitors to “pledge to never receive support from organizations that oppose reasonable gun safety legislation.”

“Receiving the ‘F’ from the NRA or the Illinois Rifle Association is OK with me — unlikely some of my primary opponents,” Kelly said in a phone interview.

Low turnout heightens the unpredictable nature of the race. Candidates need to acquire only 1,400 signatures to run, which means the field could grow or shrink after petitions are filed and challenged.

More importantly, math shows the winner could claim victory with as little as 20 percent, or maybe as a few as 12,000 votes. That was Quigley’s margin of victory in a crowded, late-winter special primary in 2009.

“Many people look at the district and they look at the geography, not the demography,” said Kevin Lampe, a Democratic consultant based in Chicago who worked on Jackson’s re-election. “People think because there’s large swaths of farmland that there’s rural territory. The greatest number of voters are in Chicago and the south suburbs.”