Threshold Ethics is a pragmatic moral framework for decision-making in emergencies—situations where all available options cause harm, delay worsens outcomes, and power concentrates rapidly.

Rejecting rule absolutism, outcome-maximization, and virtue-based ethics as insufficient for modern governance, the book introduces a threshold-based approach that permits exceptional actions only under explicit, enforceable constraints. Moral violations, when unavoidable, are treated as failures to be governed—not successes to be celebrated.

Using decision trees, governance instruments, and comparative failure analysis, the book examines historical cases and contemporary domains including artificial intelligence alignment, biosecurity and dual-use research, autonomous weapons, and emergency state powers.

Threshold Ethics does not promise moral clarity. It insists on accountability, restraint, and the preservation of moral residue when clarity is impossible.