The upcoming mini-series Spock Reflections is supposed to cover that.I also don't get why they see Spock as a traitor. Surely some other Vulcans are seeking reunification with the Romulans as well.
Is that set in the new timeline? or the old?
Ah:
Written by my pal Scott Tipton and his brother/ partner-in-scribe David, with art by David Messina of the Star Trek prequel fame, Reflections looks to be set in the new, post-film timeline established by the rebooted continuity. It should hit shelves sometime around July, just in time for the San Diego Comic-Con.
http://andrewstevenharris.wordpress.com/2009/04/03/new-star-trek-spock-reflections/
After seeing the film at a preview, I'll just say that this will be... em.. interesting..