Following Heath White, let ‘divine determinism’ denote the pairing of the following theses: ‘(1) the facts about God’s will entail every other contingent fact, and (2) the facts about God’s will are explanatorily prior to every other fact’. In the article, we develop a theological version of Peter van Inwagen’s so-called Direct Argument and show that, if sound, the Theological Direct Argument leads to the conclusion that divine determinism is incompatible with human moral responsibility. But, the soundness of the argument depends upon two inference rules, one of which, called Rule B, is controversial. So, in the third section of the article, we offer a novel, two-part defence of Rule B. This defence, in the first part, has to do with how truth, in a fairly trivial way, depends on the world. The second part of the defence has to do with the way that the logic of conditionals works. The upshot of this defence is that counter-examples to Rule B are impossible. Even so, should that defence fail, we also consider, in section four, a way of reformulating Rule B that, if successful, circumvents alleged counter-examples to the original statement of Rule B.