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BOCA RATON, Fla. – Jumpstarting his two-day tour of the Sunshine State with a visit to a retirement community, Joe Biden continued to conflate Paul Ryan’s budget proposals in the House with Mitt Romney’s plans for the presidency, citing numbers from the former to accuse the latter of endorsing massive cuts in Medicare and Social Security.

The vice president said the “press accurately points out” that he cites Ryan budget numbers to hit Romney, but Biden doubled down on his offensive, saying it’s a “fair” argument.

“If Congressman Ryan felt so strongly about insisting that this plan become law, and if Governor Romney said he would’ve signed it into law ... then it goes to their motive, it goes to who you believe,” he said to a crowd of approximately 850 people, mostly seniors, at Century Village.

“Can you imagine the president supporting a plan that would, under any circumstances, would raise the cost for seniors $6,400 your out-of-pocket?” he said, referring to a CBO estimate of the difference between projected health care costs in 2022 and the premium-support subsidy for an average 65-year-old proposed by House Republicans. As voices from the crowd shouted “No!” Biden continued, “So press, that’s why I raise it. That’s why I raise it.”

Biden opened up a new offensive on a issue particularly sensitive for seniors, charging Romney with wanting to raise taxes on social security benefits, which would he said would result in a $460 increase in taxes for the “average senior."

The Romney campaign said Biden had “fabricated” the attack on Social Security and disputed the Obama campaign’s $460 figure, which was derived from a Tax Policy Center assessment of Romney’s budget.

“These attacks will backfire when voters learn he has repeatedly supported higher Social Security taxes, and that seniors face a 25 percent across-the-board benefit cut because of President Obama’s failure to lead on this issue,” Romney campaign spokesman Ryan Williams said.

Romney defenders have criticized the Tax Policy Center study because the assessment of Romney’s budget plan was based on assumptions that the campaign has yet to detail -- yet that lack of detail also has opened Romney up to further criticism. The Romney campaign says their budget proposal to slash both taxes and the federal budget would be made fiscally sound by closing loopholes and increasing the size of the economy, but they have not yet spelled out which loopholes they would close.

Biden pounced on the lack of specifics: “Notice they will not name a single program, not a single thing, and why?”

“Well, they're doing it because they have to,” Biden said, answering his own question. “And here's the reason they have to: They cannot possibly, cannot possibly continue and add to the tax cuts for the super wealthy unless they eviscerate the rest of the budget.”

He joked, “My mom grew up dreaming one of her kids would become a millionaire. She was sorely disappointed in her son.  I hope one of my kids become a millionaire, I mean it sincerely.”

The Obama campaign sent early notice Friday signaling Biden’s impending Social Security offensive, and the Republican National Committee responded by pointing out that Biden had actually voted to increase taxes on Social Security benefits.

In 1993, Biden voted in favor of the Omnibus Reconciliation Act, which raised taxes on Social Security benefits for “higher income beneficiaries.” According to the Social Security Administration, at the time of the vote 81.8 percent of beneficiaries had no potential tax liability for their benefits. Vice President Al Gore tipped the scales of the 50-50 tie in the Senate, in favor of passage.