The church is not the kingdom of God. The church is a dispensation within the Kingdom.
Where do you get this?
Seems to me Scripture and history are filled with the understanding that the Church IS the Kingdom of God. Remember that Jesus declared the Kingdom of God WAS HERE with him. After all, where the King is, isn’t that the Kingdom?
Jesus is Head of the Church which is his Body. Where the king is, there is the kingdom. And he said he’d be with us always (and is, even physically, in the Eucharist).
Jesus is Bridegroom to the Church, his Bride. Where the king and queen are united, as the chief family and head of a nation, there is the kingdom. And we are all adopted into that kingdom family.
That the Kingdom of God is not complete yet is no surprise. Yes, we await Jesus’s Second Coming to conclusively defeat his enemies and bring his Kingdom to fulfillment. A lack of complete fulfillment now does not mean that there is no kingdom now, and takes nothing away from its unity in heaven and earth through him. Or else, by the same logic, we don’t have salvation now but have to await the final judgment. Or, in kingdom terms, that David was not the chosen, anointed king of God over the kingdom of His Chosen People, just because the promise to the Davidic Kingdom had not been completely fulfilled.
The church will not rule forever.
Oh? Matthew 16:18 “…I [Jesus] will build MY Church, and the gates of hell shall not prevail against it.”
What is hell/hades/the underworld but an end, a death? If something does not die, it lasts forever, yes?
The CC has had secular as well as spiritual dominion over territory and much political alliance, even had a standing army at once.
How is this relevant?