WASHINGTON – Mr Joe Biden accused Mr Bernie Sanders' campaign of releasing what he called a “doctored video” purporting to show the former vice-president agreeing with Republican proposals to privatise Social Security.
“It's simply a lie, that video is a lie,” Mr Biden said at a campaign event in Indianola, Iowa, on Saturday (Jan 18).
“I'm looking for his campaign to come forward and disown it but they haven't done it yet.”
He went on to lay out his plans to shore up Social Security, which he said would expand the retirement programme, not cut it.
Mr Biden has proposed lifting the cap on income subject to the tax that funds Social Security and Medicare, currently US$137,700 (S$185,532).
The clash over Social Security comes as Mr Sanders is trying to cut into Mr Biden's strong support among older voters, who tend to favour Mr Biden's moderate stances and vote in higher numbers than other demographic groups.
The two candidates are virtually tied for first place for the first two nominating contests in Iowa and New Hampshire in February, according to the RealClearPolitics aggregation of polls.
The video, circulated on Twitter on Jan 1 by a Sanders adviser, features a snippet of a speech Mr Biden gave at the Brookings Institution in Washington in 2018.
The Sanders campaign said Mr Biden could be heard agreeing with house Speaker Paul Ryan about privatising Social Security. That claim was repeated in a Sanders campaign newsletter and was judged to be false by Politifact.
The Sanders campaign responded to Mr Biden's comments on Saturday by releasing a compendium of what it claimed were Mr Biden's “repeated efforts to slash Social Security”.
“Joe Biden should be honest with voters and stop trying to doctor his own public record of consistently and repeatedly trying to cut Social Security,” Mr Sanders's campaign spokesman Faiz Shakir said in a statement.
“The (former) vice-president must stop dodging questions about his record, and start explaining why he has so aggressively pushed to slash one of the most significant and successful social programmes in American history, which millions of Americans rely on for survival.”
At a campaign event on Saturday in Exeter, New Hampshire, Mr Sanders sought to dismiss friction between the candidates, which he said obscured the real issues in the presidential race, though he didn't refer specifically to Mr Biden.
He said that if he slipped on a banana peel that would be the top headline and not important issues like poverty.
“We are going to focus on the issues of working families in America and bring them together,” he said.