Being loyal to a friend sometimes means being the one who says, “No, that’s not okay.”

Support is not the same as agreement. There are moments when the useful thing a friend can do is refuse to nod along, because everybody else in the room is nodding and somebody needs to be the one sentence of resistance. It costs you something to say it, which is the point. Agreement is free, and free support is not worth much when somebody is about to do real damage.

Say the short version rather than the speech. Name the specific thing, once, and stay in the room afterwards. And expect them to be annoyed, because people usually are first and grateful later, if at all.