I used to be a monk in the Thai forest tradition six years, a friend of Ven. Gavesako, and also used to study Vinaya a lot. In particular I did a lot of research on the neglected communal legal procedures (adhikarana-samatha-dhamma), and was preparing a book basically about them including a chapter discussing the exact meaning of 'schism' and everything related to it in Vinaya.
The latest draft is more than three years old now and I haven't looked at it all since, and I wasn't completely happy with it then- some niggling complications I never fully sorted out, but overall I'm very confident that the gist is right, i.e. the usage of the term 'schism' and 'harmony' by the Thai traditionalist faction for basically suppressing any kind of dissent and imposing superficial conformity while refusing to acknowledge let alone examine genuine issues, is wrong morally and further has no validity in terms of Vinaya.
The essence of the blameworthy kind of schism is invoking authority independent of Dhamma-Vinaya (in the original strict sense= the most reasonably probably historically authentic/original recension(s)/representations of those passages among the Suttas and Vinaya which are literally 'Word of the Buddha' or were spoken by a disciple but explicitly endorsed by the Buddha in his lifetime so long as that record of endorsement is considered probably historically authentic -anything else, spoken by disciples or by outsiders, is at best legitimate if in conformity (anulomika), but cannot ever be authoritative).
So, to invoke the authority of a Mahatherasamaghorn or Thai State law over Sangha legal issues is essentially to rely (take refuge in) an alternative religious authority, a different 'sarana', independent from Dhamma-Vinaya, and that is the essence of schism -dividing the basis for cohesion of the Sangha, which can only be Dhamma-Vinaya as taught and formulated by the Buddha, only. It is the Thai traditionalists who are responsible and blameworthy for the schism, if it is that now, and they are the Adhammapakkha -the faction of Non-Dhamma, or the ka.nhapakkha -the Dark faction. They use the same terminology, but it is all distorted, and they use it as rhetoric to threaten and bully, but they are not willing to look at evidence actually from the Suttas and Vinaya, nor examine the case properly by comparison to original Dhamma-Vinaya as the criterion, and they do not attempt to persuade reasonably or argue reasonably -which are all characteristics defined as distinguishing the adhammapakkha in the Vinaya.
The point about rushing this through to avoid discussion at the WAM is nonsense on multiple levels, but for starters -the monks interested in helping to revive the bhikkhuni ordination have been fairly patiently and deferentially trying to raise it repeatedly at WPP Thera's Council meetings for many years, and just finding it dismissed without examination and being personally ridiculed and attacked for it. The Thai faction have had more than enough opportunities to discuss it reasonably, and have failed to show any signs of intention to do so sincerely on the basis of Dhamma-Vinaya, repeatedly, over many years, so it is completely understandable that Aj Brahm and Aj Sujato have eventually gone ahead without them.
I believe it may actually turn out for the best if this division (probably 'schism' in the full technical sense, now) does not get hastily patched up and covered up, but remains. To truly resolve it down to its roots would be miraculous, but sadly extremely improbable in the foreseeable future. This is not a new division, but only a formal acknowledgment of a situation which has actually been developing gradually for many years. The Thai traditionalist faction and the radically scripturally orthodox faction (two descriptions I just made up, not the names they give themselves) have been not truly in harmony for many years, it's better to at least acknowledge the problem and now the Thai side is forced to consciously handle the problem, they can't carry on just suppressing it and covering it up with their totalitarian 'harmony' rhetoric.
At least my draft chapter explaining 'schism' contains, as far as I know/can remember, ALL of the passages from the Suttas and Vinaya referring to schism and its related terms, and a few from the commentaries, one parallel from the Mulasarvastivadin Vinaya recension on the definition of 'different communion' with a bit more built-in commentary, mostly with the original and then a translation right underneath, so you can also look for yourselves and check out the sources, and you don't just have to believe me.
I'm now at Uni in my second year and involved with about five societies and getting a bit crazily busy, so I don't want to get too involved with this really (despite the appearance of writing a loony length reply!), just wanted to offer some hard information (i.e. the chapter analysing the technical meaning of 'schism' which attached, not my personal opinions above) into the melting pot and stand back and let it stew.
(formerly Bhikkhu Santi(dhammo))
p.s. I couldn't get the attachment thingeemajiggy to work, so here's a link to it uploaded: http://sites.google.com/site/bitsandbobsofmine/draft-schism-chapter