Simmering internal tension over potential union representation at Zach Theatre took the stage in Austin City Council chambers Thursday when council members proposed requiring arts organizations that want public money to work with labor unions.

The council passed the requirements — subject to being further hashed out between now and February — after two hours of back-and-forth arguments from theater leaders, Zach employees, union organizers and other community members.

The changes to the city’s cultural services agreement require organizations that take city money or use city property to recognize any labor organization designated via a card-check method and cooperate with it. If not, they could lose funding in future years.

A Zach stagehand, who said she was representing many too afraid to speak out, said employees there have long been trying to unionize. Katie Anderson said her hours had been cut and her uniform changed as retaliation for heading up the organization effort.

Later, the pro-union forces gasped when Zach Managing Director Elisbeth Challener denied those allegations. Anderson shouted back from the audience that a manager had told employees not to sign cards to organize.*

“There is not a labor dispute at Zach,” Challener said.

Many Zach employees turned out in support of their management to say they resented efforts by a local union to push the theater to “join their little club,” as Stage Chief Taylor Novak put it.

Zach used $10.8 million in city bonds to build its Topfer Theatre and sits on city property. This year it’s set to receive $210,000 from the city. Its budget is roughly comparable to The Long Center and The Paramount Theatre, which both have employees represented by unions.

Supporters of Zach’s management argued that a check-card system of unionizing versus a secret-ballot system allowed union representatives to bully employees into joining. Meanwhile, the council measures require that theater management “maintain a neutral posture.”

Two different theater-management supporters compared that to Donald Trump getting to talk for an hour while Hillary Clinton had a sock in her mouth, or Trump having the sole power to collect and count votes and then tell Clinton who won. (Trump represented the labor union in both of those analogies, adding a layer of dissonance to the discussion.)

The council majority disagreed and approved the contract amendments over the protests of Council Members Don Zimmerman and Sheri Gallo, with Council Member Ora Houston abstaining. In February, they said, they will determine the consequences for organizations that don’t comply.

*This story has been updated to clarify Anderson’s comments. She responded while Challener was speaking, but later said she was shouting to another theater employee, Director of Production Paul Flint.