Which of the following describes a "breach of duty"?

A breach of duty is fundamentally understood as a failure to uphold legal or moral obligations. In the context of law enforcement and correctional practices, officers are expected to adhere to specific standards of conduct and responsibilities. When an officer fails to meet these obligations—whether to act lawfully, to protect individuals in their care, or to follow established protocols—they are considered to have breached their duty. This failure can lead to various consequences, including legal ramifications, disciplinary actions, or loss of trust among the community and the justice system.

The other options do not align with the definition of a breach of duty. For instance, successfully defending against a tort claim does not address any failure to perform duties; it simply reflects a legal outcome. Similarly, performing a legal requirement or committing a criminal act in self-defense relate to actions taken rather than the failure to meet obligations. Therefore, the correct understanding of a breach of duty is indeed encapsulated by the notion of failing to uphold those critical legal or moral responsibilities.