I had a to suffer through a speech this weekend about how Yaakov "the leader of Klal yisroel at the time [sic]" and the shivtay ko (his 12 sons) created a besdin (formal Jewish court) that sentenced Chamor to death.
Afterwards, I cornered the man and asked him how the scrupulously halachic forefathers could have created a kosher bes din given that they were (a) related to each other (b) related to the victim.
To his credit, the man had the good sense to say he didn't know.
What was his mistake? This: He presumes the world he dwells in today existed always. In 2006 we can't imagine a great Jewish man acting outside of the halacha, and because Yaakov, obviously, was a great Jewish man, many Jews take it for granted that he was also halachic. But this idea crumbles on examination. How for instance, could Yaakov have foreseen the development of the Mishna, the Talmud, and all the subsequent codes and commentaries? That corpus, our law, is the work of men, gifted men to be sure, but men all the same. As such, the result is contingent, not inevitable. We could have ruled like Bes Shamai and not like Bais Hillel in every instance and created a Judaism that bears no resemblance to our own and God's reaction would have been exactly what it was when the court of Rabbi Yehoshua rejected the proclomation of a Bas Kol.
As the Talmud says: "[At that time] God smiled and said “My children have defeated me, my children have defeated me.”