If not belief, then what is dharma? The Jaya alludes to an answer: ritual.
I read Arjuna's crisis at the beginning of the war as a crisis of belief. It's no surprise that he appears Hamlet like to us, vacillating between his belief in the warrior ethic and his concern for his elders and his relatives.
Krishna tells him to set aside his concern and focus on his ritual obligations. A kshatriya has to fight: doubts about the dharma of war are above his pay grade.
Can we accept this alternate theory of dharma as ritual action?
I find myself unable to believe that ritual is the antidote to belief. It seems like another sub-optimal solution to a deeper problem: how to engage with abstraction powered human ambition? We can't set aside our fascination for abstractions (at least I can't) and we can't prevent abstractions from running out of control either.
In Hind Swaraj, Gandhi blames machines for the violence of empire. I am not going to repeat his arguments here, but it's clear that one line of thinking about abstraction ends with machines. Provably so, since Turing Machines are the most general abstractions that we can conceive - as far as we know.
But machines are in a long line of abstraction that starts with God, belief and ritual and ever since we have had those thoughts (about God, belief and ritual) we have been in one sort of trouble or the other.