Look at this funny stuff in Sistani's research centre:
http://www.aqaed.com/faq/365/This is from the narrations they attribute to Ja`far:
ولا تقولوا خرج زيد فان زيداً كان عالماً وكان صدوقا ً ولم يدعكم الى نفسه وانما دعاكم الى الرضا من آل محمد (صلى الله عليه وآله) ولو ظفر لوفى بما دعاكم اليه
"Don't say Zayd rebelled, he was a truthful scholar, he never called for himself but he only called for the Rida of Aal-Muhammad, and if he had succeeded he would have fulfilled it."
Then this other similar one:
رحم الله عمي زيداّ, أنه دعا إلى الرضا من آل محمد ولو ظفر لوفى بما دعا إليه، وقد استشارني في خروجه فقلت له: يا عم إن رضيت أن تكون المقتول المصلوب بالكناسة فشأنك، فلما ولي قال جعفر بن محمد: ويل لمن سمع واعيته فلم يجبه
In this one Ja`far claims Zayd consulted with him, so he told him he would fail and be crucified but Zayd still went??? Ok hehe...
Then the Mufti tries to make excuses as to why didn't Ja`far help, so he says it's because he knew it was going to fail thus he never participated. Which never convinced the questioner because Husayn according to them also knew he was going to fail and that his women and children were going to get slaughtered yet he still rebelled.
The Mufti then replies that there are "TWO THEORIES"!!! He actually uses the word "Theory", as if the religion isn't clear and we need theories to explain why Shia beliefs are so damn self conflicting.
The first theory is that the roles of the Imams are pre-assigned by the prophet (saw) from before and what they do is from God's wisdom even if we do not comprehend it. (Meaning they don't know for sure why the heck this happened).
Second theory is that each Imam based on his infallibility fulfills his role by judging the situation as he sees fit. (Which isn't different from the first answer!!)
So that's Sistani's official research centre's answer to Zayd's revolution.