Democratic presidential contender Sen. Bernie Sanders Bernie SandersSirota reacts to report of harassment, doxing by Harris supporters Republicans not immune to the malady that hobbled Democrats The Hill's Morning Report - Sponsored by Facebook - Republicans lawmakers rebuke Trump on election MORE (I-Vt.) on Tuesday announced an endorsement from National Nurses United, the largest union of registered nurses in the U.S.

The group cited Sanders's "Medicare for All" proposal as one of the reasons it was backing the Vermont senator's White House bid.

ADVERTISEMENT

“We are so proud that together, in 2016, Bernie Sanders and NNU elevated Medicare for All to the national mainstream, where it has advanced to a top 2020 presidential race issue,” the group's executive director, Bonnie Castillo, said in a statement. “Nurses are beyond tired of watching our patients suffer and die needlessly, simply due to inability to pay, and we know Bernie Sanders is and has been, leading on Medicare for All through his advocacy and Senate legislation.”

The union also cited Sanders's labor platform, including his Workplace Democracy Act, and his support of the Protecting the Right to Organize Act; both bills bolster the power of unions across the country and lift wages.

The union, which also threw its support behind Sanders in the 2016 Democratic primary, plans to officially endorse Sanders at an event in Oakland, Calif., on Friday.

The group has over 150,000 members across the nation and has been a strong proponent of Medicare for All.

The endorsement is a win for Sanders, who has been trying to separate himself from fellow top-tier contender and progressive Sen. Elizabeth Warren Elizabeth WarrenOvernight Defense: Appeals court revives House lawsuit against military funding for border wall | Dems push for limits on transferring military gear to police | Lawmakers ask for IG probe into Pentagon's use of COVID-19 funds On The Money: Half of states deplete funds for Trump's 0 unemployment expansion | EU appealing ruling in Apple tax case | House Democrats include more aid for airlines in coronavirus package Warren, Khanna request IG investigation into Pentagon's use of coronavirus funds MORE (D-Mass.).

Warren has climbed to the top of the Democratic primary field in a number of polls and has been pushing her own version of Medicare for All.

Sanders criticized Warren's plan in an interview last week, saying it could stand to hurt workers in the long run.

"When you're putting what amounts to a $9,500 'head tax' on a company that is hiring workers for $40,000 or $50,000 dollars, that's quite a hit. Quite a hit," Sanders told the "Deconstructed" podcast.