OK, so according to Marine Public Affairs, I was wrong...or should I say the veteran crew chief who told me during one of my flights in the Osprey was wrong.
Turns out, Obama was picked up at LZ Washington in the Green Zone in the MV-22. He was flown to Ramadi, where he met with tribal sheiks there who were part of the Anbar Awakening movement. Then he reboarded the Osprey and flew to Amman.
This is logical on several levels. First, if he's going to a Marine AO for meetings with Anbar officials, it stands to reason the Corps would pick him up in an Osprey rather than a 46. The trip is faster and at a higher altitude, so at least tactically, it's safer. Also, the Osprey is the most capable aircraft for the long trip from Ramadi to Amman. A 46 would suck for that distance and the 53 wouldn't be a whole lot better. And you can't land a C-130 at Ramadi.
Hence the Osprey flight. Marine officials, though at first skeptical themselves, didn't see a publicity stunt on this one.
But I am curious about the landing at LZ Washington. That LZ is pretty tight (thought I admittedly have really only seen it at night since all of my flights out of there have been at o-dark-thirty). But I vividly remember talking to a veteran Osprey crew chief who was involved in the testing phase of the MV-22 and is now in VMM-263 that the bird couldn't land at Washington because it was too tight.
I stand corrected...