And if any WT loyalists out there say, "No, no way! It wouldn't be that way!"...
...remind them that the Org has stated in their literature - in no uncertain terms - that it very much intends to govern the planet in the "New System".
...
Then ask them to imagine the WTS being given control of a small country tomorrow...
....and then ask, "now, do you truly believe that democracy, freedom of speech, education, advances in science and medicine, and genuine equality would truly be proliferating in that country ten years on?"
If they have even a shred of honesty and half a functioning brain cell between their ears, they'll feel very uncomfortable at that question, and they'll hesitate....
...and when that happens, ask them if they'd really want to live under a regime like that...
...indefinitely.
(EDIT: IMO, this is also a good approach if you ever hear "but what if they're right?")