Hundreds of low-wage airport workers are planning a protest inside Reagan National Airport just outside Washington next week with an assist from a Democratic presidential hopeful.

Sen. Elizabeth Warren (D-Mass.) is scheduled to join catering workers at one of the airport’s terminals Tuesday as they petition the federal government for permission to go on strike, Warren’s campaign confirmed to HuffPost. It would be the latest instance of a high-profile Democratic candidate joining a protest to raise the profile of a workplace cause.

The rally is being spearheaded by Unite Here, a labor union whose members include people who prepare in-flight meals at airports around the country. Those workers are battling for new collective bargaining agreements with LSG Sky Chefs and Gate Gourmet, two industry heavyweights that contract with the major airlines.

D. Taylor, Unite Here’s president, said the eagerness of 2020 candidates like Warren to support labor’s causes and criticize employers by name marks a shift from past elections.

“I think the Democratic Party had sort of forgotten who brought them to the dance lots of times,” said Taylor, whose union represents 300,000 workers, mostly in hospitality jobs. “I think the Democrats have finally started to understand that you [can’t] be a party of workers without the labor movement.”

Unite Here has been holding a series of strike votes around the country, as The New York Times reported in June. So far more than 11,000 workers have authorized the union to declare a work stoppage, demanding a minimum wage of at least $15 an hour and more affordable health care. An additional 3,000 airline catering workers who are members of the Teamsters and the Retail, Wholesale and Department Store Union are also threatening to strike.

Taylor said that even though the workers are directly employed by catering companies, their wages are determined in large part by the major airlines that hold the contracts. He said if the union can’t raise standards at both LSG Sky Chefs and Gate Gourmet, airlines would just shift to whichever one is cheaper.

“We have to do this across the board,” Taylor said. “This is an industry that caters to airlines like American and Delta, which are making billions of dollars. There is such a disparity and our folks literally live in poverty.”

LSG Sky Chefs said in a statement that it was negotiating toward a fair agreement but “could not possibly meet the union’s demands and remain in business.”

“The stumbling block to success is the union’s demands for added wages and benefits that more than double our total cost of labor,” the company said through a spokesperson.

Gate Gourmet said it was working “in good faith” with the union and a mediator, noting that federal law would prevent “operation disruptions” by the union.

Indeed, workers employed in the airline industry can’t go on strike as easily as other workers in the private sector. Their disputes are handled by the National Mediation Board, and any strike requires a release from the agency due to the impact it could have on travel. The bar for striking is very high ― and likely even higher when the board is headed by Republicans as it is now.

The union plans to file a petition for such a release on Tuesday. A Unite Here spokeswoman said it had secured a permit to hold a protest of up to 400 people inside Reagan National Airport the same day.

In lieu of a release, the union can always put public pressure on the employers ― which is where candidates like Warren come in. It has seemed at times like Democratic presidential candidates are tripping over each other in a rush to picket lines as they compete for the 2020 nomination. Several joined Stop & Shop grocery store workers in the Northeast when they were on strike in April, and more took part in protests against McDonald’s a month later.

Those sights may be an indication of how the Democratic Party in general has shifted in the direction of organized labor recently, championing a $15 minimum wage and sweeping changes to collective bargaining laws. After the 2016 election, in which several unions were quick to endorse front-runner Hillary Clinton, most have suggested they will keep their powder dry this time and let the crowded field of candidates come to them.

Tenae Stover, a 26-year-old D.C. resident who works for LSG Sky Chefs, said a raise above $15 would make a significant difference in her life. She’s worked at Reagan National for three years, preparing meals to go on American Airlines flights. She said she started out at $8.40 per hour and now earns $13.

Stover said she was earning so little two years ago that she got evicted from her apartment, forcing her to move in with family. She’d prefer to be independent and live by herself, but her paycheck isn’t big enough to rent a one-bedroom apartment in Washington, especially after her health insurance premiums are deducted.

“It’s not easy to do my job, being on my feet eight hours a day,” she said. “We deserve $15 an hour and affordable health care. One job should be enough for all workers in the airline catering industry to be able to survive.”

Stover said she plans to be at the protest Tuesday.

“For months we’ve been bargaining for wages we deserve, but we’re not getting anywhere,” she said. “I don’t want to strike but I will.”