Start by quickly emphasizing the existence of a global elite/ruling class, which most will agree with, and then explain why a global elite requires a global response that will involve every worker. You can even call them the liberal elite and say we'll need everyone, from every country, to organize and take down the liberal elite. At this point I'll explain that the source of the elite's power is their control of multinational corporations and make the case for democracy in the workplace (can even be framed in Jeffersonian "consent of the governed" language) and bring it back to why it needs to be an international movement or else we're just making American citizens the new global elite to lord over the rest of the world. If they are ok with that outcome, they're a fascist.