Riffle the index of states to see which state moves. Every surviving state has a card, and a bigger state is a fatter card, so it comes up more often.
Spin the compass rose. That state invades whoever lies in that direction.
If there is nothing that way but open water, the fleet sails: a naval invasion lands on a far-off coast.
Roll the die:
1: the invasion collapses. The defender takes the invader's entire empire.
2, 3, 4: a quarter, half, or three quarters of the defender's land falls.
5: the defender is brought under control. It keeps its land and name but stops taking turns. When its controller next spins the civil war wheel, unification absorbs it for good; civil war sets it free.
6-10: full takeover. The defending state is wiped off the map.
Every 5th turn is a civil war turn: no invasion at all. The chosen state spins the civil war wheel: unification absorbs every state it controls (or nothing happens, if it controls none); civil war splits it 50/50 into a brand new state and sets all its controlled states free.
Conquered land is fully merged. If Kansas takes Colorado, it is simply Kansas now.
Last state standing wins.
Drag to orbit the map, scroll to zoom, hover a tile to see who holds it. Space bar spins.