My guess would be for Nokia partnering with Microsoft to build Windows Phones rather than with Google to build Android phones.

Obviously, a big part of that is Elop’s Microsoft ties (and the fact that he is said to have stayed on a bit longer after making his move known within Microsoft — something which probably wouldn’t have happened if it was considered at threatening move or bad-blood move).

But also, Microsoft appears to need Nokia just as much as Nokia needs a smartphone OS partner. While by most accounts, Windows Phones are impressive, they aren’t selling well. Microsoft is simply really late to a game already in progress. They also need a catalyst to shake things up.

A Nokia partnership would do that. And Microsoft would probably be open to making concessions so that Nokia Windows Phones are differentiated from others in a meaningful way.

While customization would be easier (and cheaper) to do with Android, Elop “Going Google” and taking Nokia with him would be the equivalent of him spitting in Steve Ballmer’s face.