Gun-control groups scored modest public relations victories last week as they engaged senators of both parties who voted against a bipartisan plan to expand the national gun background-check system. Activists pushed senators to explain their votes in public settings in their home states, part of a new campaign to keep the issue of gun-control alive as long as necessary -- which could mean the midterm elections in 2014.

Sen. Kelly Ayotte (R-N.H.), a central focus of a new campaign by gun-control groups.

The first PR victory came when activists forced Sen. Kelly Ayotte (R-N.H.) to explain several times in public settings why she voted against the background check plan.

Later in the week, Sen. Mark Pryor (D-Ark.) defused a potentially awkward situation by preempting Neil Heslin's attempts to raise a fuss at a campaign fundraiser. Heslin, whose son Jesse McCord Lewis was killed in the mass shooting in Newtown, Conn., has family in Arkansas, and had traveled there in hopes of shaming Pryor into explaining his opposition to the background-check bill during a campaign fundraiser. Pryor instead agreed to meet with Heslin this week in Washington.

Sen. Jeff Flake (R-Ariz.) also acknowledged that his sinking approval ratings were partly due to his opposition to the background-check plan, writing on Facebook that "Given the public's dim view of Congress in general, that probably puts me somewhere just below pond scum."

Senators and their aides have said that a renewed groundswell of support for stricter laws will be needed to compel Congress to debate the issue again. Supportive lawmakers are waiting to see whether new efforts by such interest groups and the White House  will put pressure on senators who voted no on the legislation to at least reconsider their stance, but they admit that the new push could take months to succeed.

But taken together, the events outside of Washington demonstrate the growing organizational strength of several groups working together to raise awareness of gun-control issues: Mayors Against Illegal Guns, the group bankrolled by New York City Mayor Michael Bloomberg (I); Americans for Responsible Solutions, the group founded by former Rep. Gabrielle Giffords (D-Ariz.); Sandy Hook Promise, a group founded by Newtown-area residents; a grassroots organization called Moms Demand Action for Commonsense Gun Laws; the Center for American Progress, a liberal think tank closely aligned with the White House that uses its popular ThinkProgress blog to highlight the ongoing campaign; and Organizing for America, the advocacy group established by President Obama to promote his policy agenda.

In the case of Ayotte, Americans for Responsible Solutions aired ads on New Hampshire airwaves that were critical of her vote, OFA asked its millions of supporters to sign an online petition calling on the Senate to continue debating new gun laws -- and MAIG and CAP deployed boots on the ground.

Consider what this reporter witnessed as he arrived at Ayotte's first town hall meeting last Tuesday in Warren, N.H.: In the dirt parking lot of the village's one-room meeting house, three twenty-something organizers were meeting with a group of elderly ladies who planned to attend the meeting in hopes of questioning Ayotte. In the group was Erica Lafferty, the 27-year old daughter of Dawn Lafferty Hochsprung, the principal of Sandy Hook Elementary who was killed in the shooting. Two bloggers from ThinkProgress were also trailing the group.

For the next 30 minutes, the organizers handed out handmade and printed signs and plotted with the women how they might compel Ayotte to call on Lafferty so she could directly confront the senator.

Here's what transpired once Ayotte called on Lafferty during the town hall meeting, as we reported in The Washington Post last week:

Speaking to the senator, Lafferty recalled a meeting in Ayotte’s Washington office the day after she voted against the background-check plan.

“You had mentioned that day the burden on the owners of gun stores that the expanded ­background checks would cause,” Lafferty said. “I’m just wondering why the burden of my mother being gunned down in the halls of her elementary school isn’t as important?”

Her voice strained by a cold, Ayotte quietly explained that she voted against the plan because it was flawed and that it wouldn’t have stopped the Sandy Hook killer. She said she did not believe that it would have stemmed the flow of illegal guns or compelled the Justice Department to aggressively enforce or prosecute existing gun laws.

“What we need to do is focus on mental health, ultimately,” Ayotte said. “But I understand and respect that you have a different viewpoint.”“I took a lot of heat, I will say, from even members of my own party that didn’t like the fact that I voted to go to debate on this issue,” Ayotte added later. “We can have strong disagreements, but ultimately everything should be debated and discussed. And I’ll continue to do that.”

In context, Ayotte was an easy target for the gun-control crowd. She was the only senator from the Northeast to vote against the background-check bill, allowing the groups to focus their efforts on one lawmaker in a relatively inexpensive media market. Unlike senators from other states who rarely engage the public in town halls, Ayotte scheduled three public meetings across the state, in accordance with a political tradition that requires Granite State politicians to regularly meet with voters in a town-hall setting.

Despite the work of the organizers on the ground, Ayotte didn't budge. She didn't apologize, announce plans to change her vote or vow to return to Washington and immediately engage on the subject.

And therein lies the proof that the push for new gun legislation will be a long process, likely requiring these groups to raise funds and target specific lawmakers in next year's congressional elections on the air, on the ground and online.

To a person, none of the women standing the parking lot thought they would change Ayotte's mind. Nancy Martlind, 64, of Sugar Hill, N.H., perhaps best understood the stakes in the coming months or years.

“We have her on the record,” Martlind said of Ayotte. “Then there’ll be another big shooting incident and we’ll know where she stands.”

Follow Ed O'Keefe on Twitter: @edatpost