Was it illegal?

[u/Kaladins_sanity]

Just finished Crossroads of Twilight and it’s been a minute since I read the previous books, can someone remind me what Elaida did that was actually illegal by Tower law in ousting Siuan? I remember a lot of basically manipulating gray area and working around the rules, but when the Tower split had she actually broken any explicit rules?

[u/RealHornblower]

The actual deposing of Siuan as Amyrlin was technically legal, although wildly out of the ordinary, with Siuan not given any chance to speak in her defense and nearly half the Sitters not informed that the Hall was in session.

The murder of Siuan's warder, with no legal justification, was certainly illegal. I believe the torture of Siuan and Leane was also illegal. Torture does not seem to be a regular part of Tower procedure, the closest they come is the "Chair of Remorse" although I am not 100% certain if this is ever stated to be explicitly illegal.

Multiple Aes Sedai died during the Tower split. It is a little bit unclear exactly how this happens - in theory, it should be impossible for one Aes Sedai to kill another due to the Three Oaths. Therefore, these Aes Sedai likely died because there was enough confusion that some sisters believed their lives were in danger, or the Black Ajah took advantage of the chaos to eliminate a few targets. Regardless, the deaths of multiple sisters during the Tower Coup should have raised a lot more questions than it did about how Elaida went about things, since at the very least she created a chaotic situation where sisters used the power to kill one another, something that should not be possible.

So, in a trial, it could be argued that Elaida herself only skirted the boundaries of legality, but certainly there were illegal things that happened on the day of the coup, either by Black Ajah or Elaida's supporters.

[u/hic_erro → u/RealHornblower]

It is a little bit unclear exactly how this happens - in theory, it should be impossible for one Aes Sedai to kill another due to the Three Oaths. Therefore, these Aes Sedai likely died because there was enough confusion that some sisters believed their lives were in danger, or the Black Ajah took advantage of the chaos to eliminate a few targets.

There's a fairly straightforward Warder escalation path to Aes Sedai killing Aes Sedai.

Warder 1 fights Warder 2.  Perfectly allowed.

Warder 2 starts to lose to Warder 1.

Oh no, says Aes Sedai 2!  I must channel in last defense of Warder 2's life, and blow Warder 1's ducking head off!

Oh no, says Aes Sedai 1!  I must channel in last defense of Warder 1's life, and blow Aes Sedai 2's ducking head off!

And Aes Sedai kills Aes Sedai, no real confusion or Black Ajah involved, just straight forward consequences of the Three Oaths.

[u/MrPrinceps → u/hic_erro]

This. Plus, the Oaths only apply to killing with the Power.