On What Grounds Can God Unilaterally Harden Pharaoh’s Heart?

The objects of such judgment were never morally righteous or neutral, but were rebels against God’s authority. Divine hardening was never arbitrarily implemented, but was in response to rejection of God’s authoritative word or standards.

Robert Chisholm Jr., Divine Hardening in the Old Testament

Chisholm makes the case that Pharaoh, well, had it coming to him with respect to God hardening his heart. A close reading that considers literary features and genres allows room for both the full force of divine intervention and the preservation of human moral responsibility.