Jolly has responded with a TV spot featuring his elderly mother and aunt, in which he says "protecting their Social Security means everything to me."
Jolly argues that it is Sink who would undermine Medicare because of Democratic-passed cuts to the program under President Barack Obama's healthcare law.
The suburban St. Petersburg district is considered a proving ground for each party's political messages and a possible bellwether for the midterm elections. Officials in both parties have said in recent days that private polls show the race to be close. Each has made late appeals for campaign cash.
Former President Bill Clinton recorded a phone call last week seeking local volunteers to help with Sink's campaign and a half dozen House Democrats emailed fundraising appeals to their own supporters on behalf of her. More than a third of Jolly's campaign contributions came from members of Congress.
While Republicans held the congressional seat for four decades until Young's death last year, the district's voters favored Obama in the past two presidential elections. In all, the candidates, their party committees and several outside groups have collectively spent almost $10 million blanketing the airwaves with largely negative ads focused on healthcare costs and Social Security.
Part of the reason is the large percentage of seniors in this district, which is 37% Republican, 35% Democrat and 24% independent. More than one in four registered voters is older than 65, a population that could make up more than half of those who cast ballots.
But in an effort to deflect Republican attacks on the healthcare law and rollout problems, Democrats also plan to prominently feature proposed Republican curbs on Social Security and Medicare in competitive races across the country.
"Those issues are paramount," said Rep. Steve Israel of New York, who chairs the House Democrats' campaign operation. "Having Republicans say that they want to cut Medicare but continue to fund massive subsidies to big oil companies ... that will be a defining theme."
Republicans answer by highlighting how some Medicare payment rates were cut by Democrats to help pay for the health overhaul. The U.S. Chamber of Commerce has spent $1.2 million on ads arguing Sink is "still pushing Obamacare," the 2010 law that it calls "a disaster for families and seniors." Another spot says Sink supports Obamacare "even though it means higher costs and lost benefits," citing reductions to Medicare Advantage, which lets seniors enroll in Medicare through private insurance plans.
Jolly has put up ads promising spending cuts, balanced budgets and replacing the healthcare law.
Sink has outspent Jolly by more than 3 to 1.
Having focused much of his campaign on the botched launch of the healthcare law, Jolly has lately found himself on the defensive about entitlement programs. On a recent morning at a senior center here, the former lobbyist devoted the bulk of his remarks to rebutting Democratic ads that say he worked for a group that wants to privatize Social Security. The spot also charges that he "praised a plan ending Medicare's guarantee."
The Republicans' national campaign committee for House candidates has poured $400,000 into TV ads, including one picturing Jolly's opponent next to Obama and House Democratic Leader Nancy Pelosi. "She's fighting for them, not for us," the ad says of Sink.
Sink, formerly the state's chief financial officer, tries to blunt the criticism in her own ads. One spot says repealing the healthcare law would "force seniors to pay thousands more for prescription drugs"
"We can't go back to letting insurance companies do whatever they want," Sink says in the ad.