Thousands of fast-food workers took to the streets on Tuesday—a year out from the presidential election— in the largest strike ever in their years-long battle for a $15-an-hour wage.

Workers from Burger King, Wendy’s, McDonald’s, KFC and other restaurant chains joined home care, child care, grocery clerks and other low wage workers to walk off the job in 270 cities across America. Participants will also be protesting at 500 city halls. In Wisconsin, workers will be marching to the Republican debate being held later on Tuesday at the Milwaukee Theater. And Sen. Bernie Sanders, who is running for the Democratic presidential nomination, addressed a crowd of low-wage workers in Washington D.C.

I stand with the thousands of workers on strike today to demand $15 and a union. In the year 2015, a job has got to lift… Posted by U.S. Senator Bernie Sanders on Tuesday, November 10, 2015

“What you are doing, and workers around the country are doing, you’re having a profound impact,” Sanders told strikers, crediting them with successful minimum wage campaigns in major American cities. “You should be very proud of what you have accomplished and now we have to finish the job – $15 bucks and a union,” Sanders said to cheers from the D.C. crowd.

We’re taking the #FightFor15 to politicians across the nation. We strike, we fight, we vote for $15! pic.twitter.com/zBjaoENque — Fight For 15 (@fightfor15) November 10, 2015

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The Fight for $15 movement, which has been backed by the Service Employees International Union (SEIU), launched in 2012 in New York City. Since then, it has had a string of successes: It helped push Seattle, Los Angeles and San Francisco to embrace a $15 wage. New York state will gradually raise its minimum wage to $15 for fast-food workers, becoming the first state in the country to set the minimum that high. McDonald’s and Target have also agreed to modestly increase employees’ pay in response to the protests.

The low-wage workers have won sympathy by explaining how they struggle to afford basic necessities like rent and utilities, even while working full-time jobs. And some strikers are showing solidarity with the Black Lives Matter movement by carrying voter pledge cards that call on citizens to address “the lasting impact of racism towards Black America.”

Amount of backpay employers will owe CA farmworkers the last over 3 1/2 yrs will be millions of dollars! #FightFor15 pic.twitter.com/YlBT7OGICX — UFW Foundation (@UFWF) November 10, 2015

President Obama has advocated a raise in the national minimum wage from $7.25 (which was established in 2007) to $10.10 for years to no avail, despite popular support for the proposal in public opinion polls. Hillary Clinton has called for a $12 per hour minimum—in line with a Senate Democratic proposal— while her rivals for the Democratic nomination, Sanders and Martin O’Malley, have said the wage should be raised to $15.

The Republican field are generally lukewarm on the idea of a minimum wage increase. Only longshot candidate Rick Santorum has said he would support it, although he has advocated for a far less dramatic $0.50 an hour raise per year for three years. Several other GOP contenders have expressed ambiguity over whether a federal minimum wage should even exist.

“The Fight for $15 movement is one of the most powerful examples of collective action. Having a voice on the job is a basic right. Using that voice and demanding it be heard is both courageous and inspiring. These workers deserve $15 an hour and a union,” said AFL-CIO president Richard Trumka in a statement on Tuesday. “Whether advocating for social justice or raising wages, working people are beginning to fully realize the power of standing together. These are the movements that will make our workplaces fairer and our communities better.”

Happening now on 125th St in Harlem, NYC. Racial justice = economic justice = immigrant justice. #FightFor15 pic.twitter.com/LZteDpNFYe — Fast Food Forward (@FastFoodForward) November 10, 2015