In late October, 35,000 women aged 55 and older in Florida’s seventh congressional district received mail stating that their congressman had voted 24 times to let “people on the terrorist watch list buy a gun.”

A mailer criticized its target, Republican John Mica, for accepting “a massive check from the gun lobby” only two days after the June 12 mass shooting at the Pulse nightclub in Orlando, which sits just southwest of the district.

The anti-Mica mailers came from Americans for Responsible Solutions, the gun safety group founded by former congresswoman Gabby Giffords and her husband Mark Kelly. The check in question was for $1,000, and it came from the National Rifle Association. By the standards of campaign spending, the sum was hardly massive, but it did portend the prominent role that gun issues have come to play in Florida as the state has become a top 2016 battleground for groups on both sides.

Between October 20 and November 2, the NRA has dropped $58,000 on mail and internet ads meant to keep Mica afloat. ARS has spent $40,000 to oust Mica, a senior House member who faces a challenge by Democrat Stephanie Murphy, a Vietnamese immigrant who became a Pentagon analyst. The cash is part a $232,000 allocation aimed at three tight House races that the group is targeting at the request of House Majority PAC, a SuperPAC working to aid Democrats.

In historically gun-friendly Florida, criticizing a candidate for supporting the NRA has rarely been a viable attack. But since the deadliest mass-casualty shooting took place within its borders less than six months ago, Democrats and gun reform groups have seized on Republicans’ gun records as a newfound vulnerability in a state where data shows that pockets of voters from all parties may be receptive to calls for stronger laws.

In Florida’s closely contested Senate race, Democratic Representative Patrick Murphy has invested heavily in ads attacking Republican incumbent Marco Rubio. In June, Rubio suggested the Pulse attack influenced his decision to reverse his plans and seek reelection to the Senate after his defeat in the GOP presidential primaries.

“When it visits your home state, when it impacts a community you know well, it really gives you pause, to think a little bit about your service to your country and where you can be most useful to your country,” Rubio told conservative radio host Hugh Hewitt in June.

Now, Murphy is turning those words against Rubio, accusing him of voting against gun reform in a series of bills the Senate took up in the weeks immediately following the shooting.

“I cannot understand how Marco Rubio would go back to Washington, D.C. and do nothing,” Christine Leinonen, whose son died in the Pulse attack, says an emotional ad released in mid-October. “I don’t think Patrick Murphy is afraid to take on the toughest problems, including gun violence, in this country.”

Rubio’s team seemed to anticipate the line of attack. In September, after Congress had moved on from considering legislation on the matter, he introduced a new bill on the so-called terror gap. His proposal, which allows the Justice Department to delay a gun purchase only if it can show probable cause that a buyer is tied to terrorism, is similar to a GOP proposal that fell short of passing this summer amid Democrats’ criticism of its effectiveness.

During those votes, Rubio opposed a Democratic plan that automatically banned gun purchases by people in an FBI terrorist screening database. (The list includes about 1 million records, of which around 5,000 pertain to Americans.) Rubio also opposed a proposal from Maine Republican Susan Collins that sought to strike a balance on the issue, banning a smaller number of suspects from purchasing and adding due process protections. But by offering his own bill, Rubio gave himself a way to rebut accusations of inaction.

Another endangered Florida Republican, Representative Dave Jolly, has also sought political cover on gun issues as he faces a tough challenge from Charlie Crist, the state’s former governor, who switched parties to become a Democrat.

Jolly’s Tampa-area district was redrawn by court order, leaving the Republican — who won a hotly contested special election in 2014 and was poised for a Senate run before Rubio’s reversal — struggling to appeal to new constituents. Jolly won an NRA endorsement in 2014 but is unrated by the group this year. In September, he sought a meeting with the Brady Campaign to Prevent Gun Violence. Jolly emerged from the sitdown to announce his support for an existing bipartisan bill tightening background check rules.

The NRA opposes that background check bill, originally introduced by four Democrats and four Republicans in March 2015. The gun group so far has not spent on Jolly’s behalf. By contrast, the NRA helped draft Rubio’s proposal, and has spent more than $2 million supporting him and attacking Murphy.

The content and placement of the NRA’s big Florida ad buys offer clues to the specific groups of voters it is attempting to rally. The group ran a commercial that attempted to link Murphy to Clinton and the terror attack in Benghazi, Libya, only in northern Florida’s Jacksonville, Pensacola, and Panama City markets, relatively conservative areas with sizable military and veteran populations. According to a model developed by Clarity Campaign Labs, which uses voter files and polling data to assess the probability that individual Americans support gun violence prevention measures, half of the voters in the Jacksonville media market are unlikely to back tighter firearms laws. In both the Pensacola/Mobile, Alabama and Panama City media markets, Clarity’s scores show that 65 percent of voters likely oppose such reforms. Those figures are sharply higher than the statewide average, which shows that only 37 percent of voters object to stricter gun policies.

Americans for Responsible Solutions is taking its own steps to zero in on voters receptive to its message. The older women who received its mailer in the seventh district, for instance, are substantially more likely than other voters in that race to support gun safety measures, according to Clarity’s data.

The ARS attack also takes advantage of redistricting that left Mica with the most Democratic constituency he has had since he first won a House seat in 1993.

“Mica has a new electorate he’s representing and he’s really out of step with them,” said Isabelle James, Deputy Political Director at ARS PAC. “Our message tested really well there, especially with women.”

Outside of Florida, ARS is working to oust Republicans in New Hampshire (Senator Kelly Ayotte) northern Virginia (Representative Barbara Comstock), and Long Island, New York (Representative Lee Zeldin). In all four races where it is invested, ARS’s messaging tends to target and to work best with female voters.

“Various groups of women are our strongest advocates and targets on this issue,” Angela Kueffler, research director for Global Strategy Group, which advises ARS and Democratic candidates, said in an email. “Democratic women, obviously, but also independent women (and suburban women and older women) and even — in some cases and especially around background checks — Republican women.”

ARS’s data reflects the larger gender divide within the gun debate: Even as the NRA puts female actors in some of its national ads, the group is mostly male. The NRA does not disclose the composition of its membership, but studies suggest about 12 percent of U.S. women own a gun, versus just under 50 percent of men, a disparity likely mirrored in the group’s ranks.

Women make up 53 percent of Florida’s 11.4 million voters. In Florida, Clarity’s model predicts 33 percent of female voters are likely supporters of gun violence prevention measures, versus just 19 percent of men.

[Photo: AP/Wilfredo Lee]