Not ever. Even when every male under the age of 50 is conscripted into one of Trump's pointless wars against former allies, Democrats won't do shit because resistance is illegal and they have an unshakably legalist worldview. Calexit was already a complete joke before their government started executing their own citizens in broad daylight with no repercussion - legal or otherwise.
Americans: stop with the escapist fantasies and start finding actual ways to fight back because your elected representatives aren't going to do it for you.