by lomn
Expanding on "yes", here's how you approach all expansions and attacks:Do I have at least 2 troops in territory A?
Then I may expand/attack from territory A, provided there are legal territories in which to do so.
Specifically, you still have things like entrenched city resistance -- if you have 2 troops in A, you can't expand into Minor City B, because you'd not have troops left in B after the resistance loss. But there is no game concept limiting your attacks or expansions save that you must leave at least 1 troop behind.