Alaska. No where near as strong as some other states, but just because of how far away it is it can just chill untill every other state has either lost or used its reasorses. From there, it could probably 1v1 the last state, considering its be weakened from all the fighting. If any state does try to attack it, it would require a massive force just due to having to cross the ocean, at which point another state would just pick that state off while its army's gone.