Not without posting the whole exchange - it was on the mailing list that Bruce Moomaw (one of the space journalists) set up. Everyone was discussing the IAU decisions, and Alan was very emphatic about not liking the final IAU decision and the way it was defined. I actually looked at his old paper (IIRC it mentioned "uberplanets" and "unterplanets", which stood out because I thought they were phenomenally unimaginative labels ) and raised the fact that his proposal back then sounded similar to what was being suggested by the IAU and asked him why he'd apparently changed his mind. I don't recall what was said after that though, it was all pretty heated and heels were being dug in all over the place .

EDIT: Having a look at the emails again, it seems his beef was that he wanted objects to be classified based on their intrinsic properties only (i.e. not external, dynamical ones), and was upset that the IAU definition seemed to be a mix of both. in the Levinson-Stern paper, "unter" and "uber" planets are classes of planets, but he didn't like that the IAU definition because apparently those aren't subclasses of planets. The discussion fizzled out shortly thereafter, but while he was evidently quite convinced that he hadn't (at the very least) changed his mind over the years, it looked very much to me like he had changed it.

Sometimes scientists can be pretty emotional about the subjects they study - he's just as human as the rest of us . But I don't think he was doing his cause any favours by starting up petitions against the IAU decision. Most of us just reckoned that the IAU would refine the definition before their next big meeting - it's much better to work within the system than to declare it useless and try to start a revolution from outside. It just seemed like so much sour grapes to me, but either way I still respect the guy.