They don't need excuses, the Regime will just manufacture one.
What we should do is develop mutual aid and federate factions together. Black Panthers should escort peaceful protestors, and peaceful protestors should render medical assistance, supplies, and shelter to those who must engage in conflict. Peaceful protest and violent resistance are the anvil and hammer of democracy.
By trying to prevent people from considering violence, the hammer of reform is stolen from us. We shouldn't allow this to happen, as it serves the interests of those who want to oppress us.
IMO, other nations like Canada, Germany, and so forth will have relations with the Blue States in a civil war. Trump's regime is a terrible trading partner, dishonest, evil, abrasive, and generally just unlikable for anyone who has good sense or pragmatism. During the 1st American Civil War, the South had major issues, because they didn't have much trade with Europe - which meant supply shortages, a lack of wealth, and so forth. That cotton may have been picked by slaves, but isn't going to become lucre if it sits in a warehouse.
After awhile, when the Blue States have a more formal coalition, I think Europe will go beyond trade to offer war support. That is the sort of thing that needs troops to be readied, mentally and materially. It would be kinda like how America was in the leadup to Pearl Harbor. We were doing stuff to indirectly support the Allies, even if our blood wasn't spilt.