Bechira / free will - Moshe Rabeinu

There is a fascinating essay by the Meshech Chochma in the introduction to Sefer Shmos (also end of kuntres "hakol tzafuy v'hareshus nesumah" in the Ohr Sameiach) arguing that Moshe Rabeinu had no bechira chofshis. It would be implausable to suggest Moshe had a real choice whether to become Hashem's agent for the geulah, or a real choice whether to act as the one to go up on Har Sinai to accept the Torah. I once wanted to say this idea which sounds so radical is actually implicit in a Mishna in Pirkei Avos. "Hamezakeh es harabim ein cheit ba al yado", one who causes merit to the masses will not come to sin, but "hamachti ain maspikin b'yado la'asos tshuvah", one who causes the masses to sin will not be afforded the opportunity to do tshuvah. The mezakeh is Moshe; the machti is Yeravam - these two are polar opposites. The Rambam explains the negetive "ain maspikin b'yado la'asos tshuvah" to mean that at some point a person loses his/her bechira and therefore cannot do tshuvah (similar to the hardening of Pharoah's heart: at some point the gift of free will is lost). The opposite good side of the coin would mean a person can lose bechira to do bad -"ain cheit ba al yado" because he cannot choose otherwise.