One of the big big problems some people have with the idea that Jesus will return to a majority-Christian earth at his second coming is that such a situation would presumably require a very significant reduction in persecution. And, after all, doesn't the bible say that Christians should expect persecution?
The obvious thing to say upfront is that Christians will always suffer until the second coming (in their struggle against sin, in their coping with a dying and decaying body, in their having to set aside their own interests to serve and honour others etc.). But should all Christians at all times in history expect to experience suffering of the persecution variety? Here are my initial problems with such a view;
A. It hasn’t been true for all Christians throughout every period of history.
B. It isn’t true for all Christians throughout the world now.
C. A and B haven't always been because of unfaithfulness/compromise/laziness. Sometimes it has just been because of significant levels of gospel progress. (I wonder if one of the reasons white western middle class Christians might feel uncomfortable about postmill'ism is because we carry a lot of guilt about not being persecuted and fear, perhaps correctly, that this might be because we aren't being that faithful)
D. Once we’ve allowed for A-C, and if we think that the bible does predict a time when the gospel will have made such significant progress across the whole world that it can be said to have ‘conquered’, or the kingdom can be said to be the largest of all the kingdoms in the world, then it follows that persecution would be strikingly rare in some parts of the world at that time.
Or, put it another way. I imagine that after his conversion, there was a significant reduction in the persecution of Christians who (so to speak) lived on the same street as Saul of Tarsus. All postmillenialism is doing is saying that what God did to Saul of Tarsus' neighbourhood he is progressively doing (not necessarily in a linear fashion) throughout the world across history.
Sometime soon I'll blog some more about this, perhaps especially about the nature of the cross-shaped Christian life and how this is in no way incompatible with an optimistic eschatology.