I believe you are thinking about representative bodies (maybe the equivalent of UA for undergrads, or GSC for grads, at MIT) while the union in the news is empl

I believe you are thinking about representative bodies (maybe the equivalent of UA for undergrads, or GSC for grads, at MIT) while the union in the news is employment-based and is the sole legally recognized entity to negotiate salaries, employment conditions, etc. on behalf of MIT graduate students.