Why does Obie silently acquiesce to Archie's demands even though he knows they are wrong?

Having been Archie's errand boy for a long time, Obie finds it impossible to stand up to him. And the one time he does, with the black box of marbles from the Vigils, the box does not do "its job" to curb Archie's power. The small rebellion that Obie tries, does not work so Obie is stuck with being Archie's "slave" in many areas doing many "stupid, wrong things."