Vito did NOT "break his promise and code of honor", because the peace was not broken while he was alive, neither by him nor any of the other Families.

However he had to know that once he was gone, then others would most certainly move in to break the peace and whoever that was, their first logical move would be to assassinate Vito's successor...Michael. Therefore, he had to have advised Michael of what was to come, and plan accordingly. But make no mistake, every single murder committed on that baptism/massacre day was on Michael's order, not Vito's ... regardless of who 'conceptualized' the move.

"Can we attribute Mary's death to Vito's actions?"

Probably not, since it occurred some 20+ years after Vito's own death.

But suppose for the sake of discussion we venture out on a limb and say that yes, Vito's actions 'indirectly' led to Mary's death.

In that case, we could also justifiably attribute Fredo's death to Vito's actions.

But of course...that's another thread!

Maybe.

Apple