The American Federation of Teachers has said it will support teachers if they decide to strike in districts that choose to reopen schools without heeding necessary precautions.

The ATF said strikes for its 1.7 million members should be a “last resort,” The New York Times reports. Still, this new authorization vote will give union representatives extra power when negotiating what would be acceptable safeguards for teachers and school employees.

The U.S.’s second-biggest teachers union is also urging schools to delay reopening until coronavirus transmission rates dip below one percent and average daily test positivity rates remain below five percent—records that most districts haven’t reached. A recent Times report discovered that only two of the nation’s 10 largest school districts, Chicago and New York City would be able to reopen under those guidelines.

Moreover, the union wants to implement efficient contact tracing in regions that reopen classrooms, require teachers and students to wear masks, update ventilation systems in school buildings, and enforce six feet social distancing rules.

“We will fight on all fronts for the safety of our students and their educators,” the union’s president, Randi Weingarten, said this week. She pointed to the federal government advocating for the cruise industry and hedge funds during the pandemic, saying, “they sure as hell can help working families, and can help educators ensure our kids get the education they need.”

Education leaders have said that in order to reopen schools safely, they would need hundreds of billions of dollars. On Monday, Senate Republicans proposed a stimulus package that would allocate $70 billion for K-12 education, however, the bill stipulates that two-thirds of the money will only be allotted if schools partially reopen in person. This has become a concern for Trump, who hopes to see the economy pick up once parents can return to work.

The AFT’s resolution permits local chapters to choose whether they plan to strike. The Florida Education Association sued Gov. Ron DeSantis and other officials earlier this month, so as to block schools from reopening as COVID-19 cases continue to swell.