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.
2-5: a portion falls: 20%, 30%, 40% or 50% of the defender's land.
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 means nothing happens, civil war splits it 50/50 and a brand new state is born, which joins the wheel.
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.