It must "substantially impair" the defendant's ability to either: under the nature of his or her conduct; form a rational judgment; or exercise self-control.

The speech disorganization criterion is only met if it is severe enough to substantially impair communication.

Whether the abnormality substantially impaired the defendant's mental responsibility for the killing is a question of degree for the jury.

His lawyer, Lynn Armentrout, argued, "The state doesn't have the power to undo or substantially impair a private contract."

The abnormality of mind must substantially impair, but need not totally impair, the defendant's mental responsibility.

The judge decides whether the jurors' attitudes toward the death penalty would prevent or substantially impair their ability to decide on sentence fairly.

"Confining the president's authority to traditional combat zones thus would substantially impair the ability of the commander in chief to engage and defeat the enemy forces."

First, the state regulation must not substantially impair a contractual relationship.

The antitrust laws prohibit intercorporate acquisitions of stock or assets whose effect may substantially impair competition.

"If we fail to recognize target standing, we would substantially impair enforcement of the antitrust laws to protect against anticompetitive takeovers," the court wrote.