Labor leaders are rallying this afternoon in support of teachers at three charter schools who’ve formed a union. If they’re recognized by the state, they’ll be the first unionized charter school teachers in Chicago.

This is a big deal for teacher unions, who’ve argued that charter schools are an attempt to bust unions.

The president of the American Federation of Teachers flew to Chicago to rally teachers today. Randi Weingarten:

WEINGARTEN: What a union contract does is it gives voice to teachers, it allows them to take risk, it allows them to try new things without having an off-with-your-heads approach.

The teachers seeking union recognition work at three schools run by the nonprofit Chicago International Charter School.

They say they want more of a say in how the schools are run—and freedom to express ideas without risking their jobs.

Charter supporters have argued that unions can get in the way of needed school reforms, such as longer school days.

The school is fighting teachers’ efforts to unionize.