Many a Christian might dismiss Eschatological Victory by Christ and His Church because of the current prevalence of Satanic Secularism and Mystery Babylon all around us. How can you be a postmillennial and proclaim Christ Conquering all Nations before His Return?
This is because it is a long term view. Postmillennialism understands we are not even close to being the terminal generation. We view this as still being part of the Early Church and not the last generation. In addition, the spread of The Kingdom grows slow and gradually like the Mustard Seed. Just because we cannot yet see it being a reality does not mean it will not be.
When you make that change you realize this is simply part of tribulations prophesied by Christ Himself in Scripture. All to take place between His Ascension and Second Coming.
Even if Babylon tries and temporarily for a time got a One World Empire it is under the feet of Christ. God is Sovereign over all things and the King is like water in God's hands. He or them is not an autonomous entity that God cannot cast down at anytime per His timing.
Christians need to keep their eye on the prize and the prophecies that speak of Christ Conquering all things. Slowly building up His Kingdom over the Earths Nations. That we win and we should not get bogged down on what is happening now or even in the near future tossing out the Victory in the long term.