News stories seem to be capturing some anxiety–including some from those who should know better–about the possibility of Pope Benedict XVI getting in the way of the new pope, whoever he is. The two-pope worry is actually nothing to worry about because, simply put, there is only one papal office.
Church historians may object that we have had multiple popes at one time, which was a source of schism, but of course the difference there is that there were two (sometimes three) claimants to the papal office, each elected by rival consistories. That was indeed a problem–but not at all like what we are facing now. On the contrary, Pope Benedict has renounced the papal office–he feels unable to do it anymore–and I imagine that he wants to be left alone with his books and his time for prayer.
I suppose there will be questions about what to call him–Joseph seems like a good idea, and he has continued to publish using his baptismal name. And perhaps his successor will create some new honorary title for him: Ex-Pontifex? Probably not.
The real danger is not the retired pope, but the Vatican operators that continue to run the day-in, day-out Vatican apparatus. If I were the new guy, I wouldn't be looking over my shoulder for Benedict's interference but to the Secretary of State's office or some other seat of power. Given the fact that one of Benedict's (and John Paul II before him) weaknesses has been managing his inner circle, I think the Curia is more a cause for concern.