Tammy Duckworth spent 10 minutes calling Bingo numbers during a game at the Bloomingdale Horizon retirement home, then she took questions.

The first was predictable enough: What are you going to do for seniors?

“First and foremost,” Duckworth began, “I’m going to preserve Medicare and Social Security. I’m not going to let them turn Medicare into a voucher program.”

Duckworth is a Democrat running for Congress in a district in the Chicago suburbs, and “them,” of course, is shorthand for Republicans, mostly Mitt Romney and his new running mate, Rep. Paul Ryan of Wisconsin, whose Medicare proposal reemerged this week as the favorite blunt-force instrument of congressional Democrats in their fight to retake control of the House.

Ryan’s elevation to the national GOP ticket has allowed Democrats to reprise their savaging of the Ryan plan with tactics they know well, having used them to great political effect over the past two years.

Last week, the Democratic Congressional Campaign Committee unleashed a barrage of attacks on Republican candidates with a series of robo-calls in about 50 congressional races. And the first of the DCCC’s television ads since Ryan joined the GOP ticket was launched Thursday; it targeted freshman Rep. Dan Benishek (R-Mich.) for his vote in support of Ryan’s Medicare overhaul.

The ad features a clip of Benishek praising efforts to “privatize” Medicare and Social Security.

Democrats think this is a winning issue for them and are gleeful that Ryan’s higher profile has made it the center of the campaign debate.

Duckworth and other Democrats said Ryan’s addition to the Republican ticket only amplifies concerns they’ve discussed for months.

“You’ve got all these Harry Houdinis all over the country trying to untangle themselves from the Ryan budget,” said Rep. Steve Israel (D-N.Y.), chairman of the DCCC. “And we’re not going to let them.”

Duckworth, for example, told the crowd that Ryan’s proposal would abandon seniors, leaving them to fend for themselves.

“My concern is that I don’t want my mom to have a $600 voucher and tell her, here, you go negotiate with an insurance company on your own,” Duckworth said. “I don’t think that’s right.”

Those in the room in Bloomingdale agreed.

“This is really ridiculous,” said Fran Powrozek, 82. “We’re citizens. We don’t have enough money to live on the way it is. They already cut my insurance for prescription drugs.”

But Powrozek and her bingo partners admitted Thursday after Duckworth spoke that they don’t know much about Ryan’s plan.

“For two or three days, they’ve been talking about him on TV,” Jean Corbeil, 75, said. “They say he’ll be good — I don’t know.”

Ryan’s plan leaves Medicare benefits untouched for current retirees but, over time, would shift the program from an open-ended guarantee of care to a capped payment to seniors for them to use to purchase private insurance.

Ryan and Romney have worked to neutralize the attacks by slamming Democrats for including cuts to Medicare providers in the 2010 Obama health-care overhaul. Ryan assumed those same cuts in his budget proposal adopted by the House this year, but Romney has said he would restore them.

“We want this debate. We need this debate. And we will win this debate,” Ryan told a crowd in Oxford, Ohio, last week.

House Speaker John A. Boehner (R-Ohio) told his fellow Republicans on Thursday not to fear the Democratic attacks on the Ryan budget. During a conference call, he implored his colleagues to remember their year-long focus on job creation and the economy.

“The best defense on Medicare is a good offense,” he said. “And Paul Ryan gives us the ability to play offense.”

And on Friday, the National Republican Congressional Committee launched an offensive, releasing a new ad titled “Medi­scare” that targeted Rep. Mark S. Critz (D-Pa.).

The race is on now as each side tries to define the Ryan proposal in order to reap some political advantage with voters.

Duckworth’s opponent is GOP incumbent Rep. Joe Walsh, who echoed Boehner’s line Thursday. “I’m not defending Ryan’s plan, I’m staying on offense,” he said in an interview. “Tammy Duckworth and Democrats are going to run around scaring seniors, and I don’t think it’s going to work. I think America is ready to grow up.”

Nobody asked Walsh about Ryan’s plan when he met with supporters Thursday night at a barbecue restaurant 10 minutes from where Duckworth spoke. But afterward, retired flight attendant Pat Fedorski, 68, said she was proud of Romney’s selection of Ryan.

“The left likes to call our Republican vice presidents stupid,” she said. “They said George Bush was stupid, Dan Quayle was stupid. You can’t call Paul Ryan stupid. He’s brilliant, and he knows the budget.”

Fedorski said Democrats may attack Republicans for wanting to reshape Medicare, but “the big fat elephant in the room is that Medicare can’t be sustained — everyone knows it. Paul Ryan has the guts to say it.”

Some Republican candidates and strategists, worried about polling data on the popularity of Ryan-like Medicare changes, are working to distance themselves from the House budget chairman, however.

In a conservative district in western New York where Rep. Kathy Hochul (D) won a special election last year that was widely seen as a referendum on Ryan’s budget, an adviser to Republican challenger Chris Collins told a television station he does not support Ryan’s budget cuts. Brendan Doherty, a Republican running in moderate Rhode Island, has said the same, as has Maggie Brooks, a Republican running in Upstate New York.

Christie Vilsack, a Democrat who is challenging Rep. Steve King (R-Iowa), said she first raised questions about Ryan’s budget plan when she launched her campaign last year.

“Seniors want to make sure we follow up on our promise,” Vilsack said Monday at the Iowa State Fair. “We made a promise to them when they worked hard their whole lives that they would have Social Security, that Medicare would take care of them, that they would be able to enter a nursing facility.

“So we need to make sure we do that.”

In response, King said Ryan’s plan won’t affect current beneficiaries, meaning Vilsack and other Democrats mislead voters when they say that Republicans want to “end Medicare as we know it.”

“That phrase — ‘as we know it’ — will become very well known as the classic weasel phrase,” King said during an appearance Monday at the fair. “If you change my hairdo — if you pull one hair out of my head — you have changed my hairdo ‘as we know it.’ ”

But at the senior home in Bloomingdale where Duckworth spoke Thursday, the attack line resonated.

Asked what she knew about Ryan’s plans to overhaul the program, Tess Castell, 76, said, “Essentially, it’s a revamping of Medicare as we know it.

“Beyond that, I don’t know a great deal.”

Helderman reported from Washington. Felicia Sonmez in Oxford, Ohio, contributed to this report.