The transition organization for President-elect Joe Biden announced its "agency review teams" on Tuesday, and among those who will be laying the groundwork for the Biden-Harris administration are a senior adviser to Sen. Bernie Sanders and the former chief of staff to Sen. Elizabeth Warren

The agency review teams are the group of hundreds of people that will examine the status of the federal bureaucracy ahead of the Jan. 20 inauguration and potentially staff its agencies themselves once Biden and Vice President-elect Kamala Harris take office. The transition organization said Tuesday that the teams "have been crafted to ensure they not only reflect the values and priorities of the incoming administration, but reflect the diversity of perspectives crucial for addressing America’s most urgent and complex challenges."

On the list are Josh Orton, a senior adviser to Sanders, I-Vt., and Anne Reid, who was previously the chief of staff to Warren, D-Mass. During the Democratic presidential primary, Warren and Sanders were the two most vocal supporters of Medicare-for-all, a single-payer health insurance plan that would eliminate private health insurance and replace it with one insurance provider, the government. 

Biden during the primary and through the general election vocally opposed a single-payer plan, declaring, "That is a lie... I am the Democratic Party right now" during the first presidential debate in response to accusations by President Trump that he is at the helm of a party that favors "socialist medicine."

President-elect Joe Biden speaks at The Queen Theater, Tuesday, Nov. 10, 2020, in Wilmington, Del. (AP Photo/Carolyn Kaster)

BIDEN TRANSITION REVEALS 'AGENCY REVIEW TEAMS' AMID SPAT OVER TRANSFER OF POWER

A member of the Biden transition organization noted that it is the job of the Biden campaign to formulate policy and simply the job of the transition and its review teams to ensure that Biden and Harris can hit the ground running on Jan. 20 to implement the campaign's policy goals.  

But his agency review teams, which encompass hundreds of individuals that could eventually staff the agencies they are evaluating, appear to give a voice to those who favor Medicare-for-all and other similar highly progressive policies.

"The strong, progressive values of many of the ART members, in addition to the deep roots in the labor movement, will set the tone for the incoming Biden-Harris administration," the transition team said in a statement to Politico

Notably, both Sanders and Warren are interested in Cabinet positions in a Biden administration. Warren is widely rumored to want to be the treasury secretary, while Politico reports Sanders is interested in labor secretary.

Another highly progressive voice on the Biden transition team is Perrie Briskin, a health care professional and recent masters graduate from the University of California, Berkeley. In a 2019 essay for Vox, Briskin said she "studies universal health care." In that article, she spoke favorably of Medicare-for-all.

Moreover, Briskin signed multiple letters expressing support for single-payer health care and Medicare-for-all in her role with the University of California Student Workers Union. 

One of the letters, pushing California Gov. Gavin Newsom to establish a statewide single-payer system, panned "the failures of our employment-based health insurance system" and said California should "lead the way for our country to provide health care to all through a single-payer system. This means eliminating the unjust role of insurance companies, whose bottom line is a higher priority to them than saving lives and caring for our people."

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The other letter supported Sanders' Health Care Emergency Guarantee Act, which is essentially temporary Medicare-for-all during the pandemic. 

"While we believe that the best long-term solution is establishment of a single-payer Medicare-for-All national health program," the letter said, "we recognize the value of two interim measures the federal government can and must take immediately to protect our security and ensure our survival."

Briskin also advocated for single-payer health care in other public forums.

Members of the far left of the Democratic Party, who advance policies that Biden has explicitly said he disagrees with, are not the entire Biden transition team, however. 

Luciana Borio, a member of the Health and Human Services agency review team, is a former member of the National Security Council under former President Barack Obama, where she specialized in biodefense preparedness. In February, she co-authored an op-ed in the Wall Street Journal with former Food and Drug Administration Commissioner Scott Gottlieb on the need for increased coronavirus testing. Gottlieb served as the Trump administration's FDA chief from May 2017 to April 2019.

Democratic presidential hopefuls Massachusetts Sen. Elizabeth Warren and Vermont Sen. Bernie Sanders speak ahead of the ninth Democratic primary debate of the 2020 presidential campaign. (MARK RALSTON/AFP via Getty Images)

BIDEN TRANSITION HANGS IN LIMBO, AWAITING GSA CERTIFICATION

Also notable is Linda Thomas-Greenfield, a career State Department official who was first appointed to an ambassadorship by former President George W. Bush in August 2008. Thomas-Greenfield was one of the State Department officials who was forced out at the beginning of the Trump administration. She leads the Department of State agency review team. 

Perhaps the most high-profile single individual on the agency review teams is Leandra English, who earlier in Trump's term was part of the standoff with former Consumer Financial Protection Bureau (CFPB) Acting Director Mick Mulvaney over succession at the agency. English heads the CFPB review team.

There are many others on the Biden agency review teams who appear to be career public servants or academics who lean left but not as far left as the Sanders and Warren wing of the party.

Fox News reached out to the Biden campaign for comment but did not receive a response. 

The move by the Biden transition organization to announce the agency review teams comes as Trump still refuses to concede the election despite what experts concur are insurmountable vote margins for him to overcome in several states, even if the legal action being taken by his campaign does succeed in throwing out some votes and finding some fraud. 

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The Biden transition is in a sort of limbo as the General Services Administration (GSA) still has not issued its ascertainment that Biden is the president-elect. This is preventing Biden's transition organization from accessing government funds and offices or receiving intelligence reports that are traditionally given to presidents-elect. 

Meanwhile, according to reports, the Trump White House and political appointees are instructing career officials not to cooperate with the Biden transition organization until the GSA issues the official determination that Biden is the president-elect. 

The GSA said that its decision to not yet determine that Biden is president-elect is consistent with precedent established during the 2000 Bush-Gore legal fight. But the margins in the states Trump is pursuing legal action in are much higher than in Florida in 2000. And there are several states in which Trump trails that he would have to change the results by tens of thousands of votes to have a chance at remaining in the White House, rather than just one. 

The Associated Press contributed to this report.