Commonwealth v. Drum
Supreme Court of Pennsylvania
58 Pa. 9 (1868)
William Drum was charged with killing David Mohigan following a history of disagreements between the two men. The prosecution alleged Drum armed himself with a dagger intending to use it on Mohigan, encountered him in a saloon, and, while Mohigan was fighting with someone else, approached and stabbed him in the side, killing him. Drum's own account differed: he claimed the knife was his ordinary hunting knife, carried because he was preparing for a hunting trip; that Mohigan had been waiting to "whip him" and eventually came into the saloon and attacked him, striking him repeatedly; and that, with no way to escape, he drew the knife and stabbed Mohigan in what he described as self-defense.
Whether a defendant may be guilty of first-degree murder where proof that the killing was willful, deliberate, and premeditated was not express, but only implied.