New Jersey

unless it was part of a display being used specifically to discuss current national political events involving Trump and "the resistance". In that case there should have been other gear displayed with different / opposing messages, to represent the spectrum of opinion.

Trump is horrible beyond words but the teacher is there to teach her subject, and to teach kids how to think critically in that subject and beyond. Not to wave her own political position around.

Would it be okay if she'd done similar with an anti-Obama shirt? What about an anti-Democrats shirt? Or Trump2020?

I don't think so.

This stuff is easy. I don't know why so many conservatives, and at times even liberals, have problems with it.

A) no politics in the workplace unless it is directly related to the work being paid for.

B) when in doubt, substitute the opposite party/candidate. It can't be okay to do it anti-Trump if the same thing anti-Obama is not okay.