Sen. Bernie Sanders' presidential campaign sent a memo to staffers and surrogates Monday evening spotlighting "stark" policy differences between Sanders and Joe Biden on Social Security, trade, and other major issues after the former vice president received a wave of high-profile endorsements on the eve of Super Tuesday.

"Voters face a decision between Bernie's working-class movement and his message of change, and Biden's effort to—in his own words—make sure that 'nothing will fundamentally change' for the billionaire class that buys elections."
—Sanders campaign memo

The memo (pdf), authored by Sanders campaign manager Faiz Shakir and senior adviser Jeff Weaver, characterizes Biden's endorsements from Pete Buttigieg, Sen. Amy Klobuchar (D-Minn.), Beto O'Rourke, and former Senate Majority Leader Harry Reid as part of an effort by the former vice president to "coalesce the Washington establishment and its big donors around his campaign to protect the status quo."

"Heading into Super Tuesday," the memo continues, "the choice in the Democratic primary is now crystal clear: voters face a decision between Bernie's working-class movement and his message of change, and Biden's effort to—in his own words—make sure that 'nothing will fundamentally change' for the billionaire class that buys elections."

"With Biden bankrolled by a super PAC and boosted by billionaire donors, the primary is far from over," the document declares. "We are now entering the phase of the primary in which the differences between Bernie and Biden will take center stage."

David Sirota, speechwriter and senior adviser to the Sanders campaign, echoed that message in social media posts on Monday.

"It is organized money versus organized people," Sirota tweeted, "as it always ends up being in every consequential battle in history."

The memo points to Biden's decades-long record of advocating for cuts to Social Security, a history the Sanders campaign argues could harm Biden's chances in a potential general election match-up with President Donald Trump.

"Joe Biden spent 30 years trying to cut Social Security, while Bernie fought those cuts and pushed to expand the program," the memo says.

The document also highlights Biden's votes as a Delaware senator in favor of the 1994 North American Free Trade Agreement (NAFTA), the 2003 invasion of Iraq, and the 2005 bankruptcy bill. By contrast, Sanders voted against each of those.

"These differences make clear that the choice between these two candidates is stark—it is a choice between the party's core economic and social justice agenda, and the Washington establishment's agenda that aims to protect and enrich the wealthy and well-connected," the memo says. "The differences also spotlight how Bernie's agenda is a far more popular general election agenda than Biden."

Read the full memo: