In an email sent this afternoon, Vermont Sen. Bernie Sanders urged his New York supporters to vote for Hillary Clinton on the left-wing Working Families Party line—asserting the third party comes nearest to his “vision of democratic socialism.”

The labor-backed WFP endorsed independent socialist in the New York’s April Democratic primary, to chagrin of a number of its union founders and elected supporters. After Clinton sealed the Democratic nomination, the party agreed to put her atop its ballot line—Row E—in the Empire State

“I ask that you not only vote for Hillary Clinton, but that you vote for her on the Working Families Party line,” wrote Sanders, who backed Clinton himself in July. “Why? Because the WFP is the closest thing there is to a political party that believes in my vision of democratic socialism. The WFP shares my view of a society and an economy that works for everyone, not just the wealthy and well-connected.”

Sanders went on to assert “we desperately need” entities like the Working Families Party, and cited their support for an array of liberal policies on labor, elections and environmental issues.

“The members and leaders of the WFP have led the fight for true campaign finance reform in New York. They have won higher wages, paid sick time, and paid family leave for working people in the Empire State. They helped ban fracking,” he continued. “They have fought the billionaire class from the very first day the Party was formed.”

“Let’s vote for Hillary Clinton, but let’s also show the world that we want a political revolution, that we want to transform New York and the nation. And that’s what voting for Secretary Clinton on the WFP line will do,” he added.

The WFP, like the Conservative and Reform parties, capitalizes on New York’s fusion voting laws—which allow small third parties to cross-endorse Democratic and Republican candidates. The party almost always lends its line to left-liberal Democrats like Mayor Bill de Blasio, though in select scenarios it has also run its own candidates or simply supported the likely winner.

Bucking state Democratic leaders and numerous unions and backing Sanders for president granted the WFP a do-over of its controversial 2014 endorsement of Gov. Andrew Cuomo. Cuomo enjoyed the backing of organized labor despite the pro-business policies he pursued in his first term, and was all-but guaranteed a second victory.

Gubernatorial races are particularly important to New York’s third parties, since they determine who will have a row on the ballot for the next four years and where that line will be. But backing the centrist governor instead of his longshot challenger, Fordham Law Professor Zephyr Teachout, caught the WFP considerable flak from the left.

Sanders was the marquee speaker at the Working Families Party’s fundraising gala last month, where numerous politicians who had backed Clinton in the primary lavishly praised the senator.

Both Clinton and Donald Trump live and maintain their campaign headquarters in New York, but the Democratic nominee is virtually assured to carry the state by a massive margin.

Read the full text of Sanders’ email here:

Sisters and Brothers – There are only three days until the end of this election. I have a special request. I ask that you not only vote for Hillary Clinton, but that you vote for her on the Working Families Party line. Why? Because the WFP is the closest thing there is to a political party that believes in my vision of democratic socialism. The WFP shares my view of a society and an economy that works for everyone, not just the wealthy and well-connected. We desperately need such organizations in American politics. The members and leaders of the WFP have led the fight for true campaign finance reform in New York. They have won higher wages, paid sick time, and paid family leave for working people in the Empire State. They helped ban fracking. They have fought the billionaire class from the very first day the Party was formed. Together with progressives in the Democratic Party, with trade unionists, low-income activists, environmentalists, Occupy, Dreamers, the People’s Climate March, Black Lives Matter, and Our Revolution, the Working Families Party is a powerful force for decency, equality and sustainability. Let’s vote for Hillary Clinton, but let’s also show the world that we want a political revolution, that we want to transform New York and the nation. And that’s what voting for Secretary Clinton on the WFP line will do. Please add your name to commit to vote for Secretary Clinton on the Working Families Party line on Tuesday to help the Working Families Party’s power in New York State. Thank you. Bernie Sanders

Disclosure: Donald Trump is the father-in-law of Jared Kushner, the publisher of Observer Media.