But Sanders, it says, would “end Culinary Healthcare” and “require Medicare for All” if elected president.

Sen. Elizabeth Warren of Massachusetts, who has embraced Sanders’ Medicare proposal with a three-year transition period, would “replace Culinary Healthcare” at the end of the transition period or at the end of collective bargaining negotiations, the flier says.

The union has yet to endorse any of the Democratic presidential hopefuls. But its one-pager was viewed as an attempt to blunt Sanders’ momentum in the state, where scant polling has shown him in the lead, and prompted backlash online. The flier’s circulation also coincides with heightened fears among the party establishment about putting a self-declared democratic socialist and Medicare for All proponent atop the ticket.

But the group, which boasts 60,000 members from the hospitality industry in Las Vegas and Reno and bills itself as the one of the state’s largest health care consumers, doubled down on its criticism amid the outcry from supporters of the senator.

“Our union believes that everyone has the right to good health care and that health care should be a right, not a privilege,” said Geoconda Argüello-Kline, the group’s secretary-treasurer, adding that the union had already negotiated its own health care plan for “what working people need.”

Argüello-Kline added: “Workers should have the right to choose to keep the health care Culinary Union members have built, sacrificed for, and went on strike for 6 years, 4 months and 10 days to protect.”

“It’s disappointing that Senator Sanders’ supporters have viciously attacked the Culinary Union and working families in Nevada simply because our union has provided facts on what certain health care proposals might do to take away the system of care we have built over eight decades,” she said, noting that Sanders had participated in Culinary town halls and toured the union’s facilities.

The future of union-negotiated health care plans has been a major point of contention surrounding single-payer plans like the one Sanders and Warren have backed, and has split union leaders. Opponents of Medicare for All have argued that such a system would boot union workers off their hard-won insurance plans, with no guarantee that a single-payer system would be as good.

Sanders has specified that under his plan, businesses whose workers have union-negotiated coverage would have to renegotiate their contracts if single-payer became the law of the land — and direct any windfall to the employees.