That was true 10-20 years ago, but in a world with "terminators" I don't think it's true anymore.
Regarding effective conquest, we can look at the historical lesson of Rome. Conquest is effective when you can co-opt local leaders and cultures to cause them to identify with the conquering culture. Conquest that doesn't cause integration is historically unstable.
Regarding effective conquest, we can look at the historical lesson of Rome. Conquest is effective when you can co-opt local leaders and cultures to cause them to identify with the conquering culture. Conquest that doesn't cause integration is historically unstable.