Under Pennsylvania law, there is a big – often unnoticed – distinction between the use of deadly force for self defense as opposed to the mere use of force for self defense. The distinction is frequently missed by even the most seasoned criminal law practitioners, but is crucial to understanding a defendant's trial rights.

Use of Deadly Force in a Self Defense Case

In Pennsylvania, a claim of self-defense in a criminal case, where the force used was deadly (as in a gun or knife), requires the defendant to present evidence establishing three key elements:

1. The defendant must have reasonably believed that they were in imminent danger of death or serious bodily injury and that it was necessary to use deadly force to prevent such harm
2. The defendant must have been free from fault in provoking the difficulty which culminated in the use of deadly force
3. The defendant must not have violated any duty to retreat

Once the defendant introduces some evidence to support a self-defense claim, the burden shifts to the Commonwealth to disprove the self-defense claim beyond a reasonable doubt.

No Duty to Retreat Exception: There is no duty to retreat if the defendant is not engaged in criminal activity, not in illegal possession of a firearm, is attacked, has a right to be in the place where attacked, and the other person uses or displays a firearm/deadly weapon. § 505.

Imperfect Self-Defense: If the defendant's belief that deadly force was necessary was unreasonable, but they genuinely believed they were in imminent danger, they may be found guilty of voluntary manslaughter under the defense of imperfect self-defense.

Justification as a Defense (§ 503)

Justification as a defense allows an actor to avoid criminal liability if they believe their conduct was necessary to avoid a harm or evil to themselves or another, provided that the harm sought to be avoided is greater than that sought to be prevented by the law defining the offense charged.

To be entitled to a jury instruction on justification, the actor/defendant must show:

1. They were faced with a clear and imminent harm, not speculative
2. They could reasonably expect their actions to be effective in avoiding this greater harm
3. There was no legal alternative to abate the harm
4. The legislature has not precluded the defense

Use of Regular Force in a Self Defense Case

Regular self-defense (non-deadly) is specifically codified under § 505. It allows the use of force when the actor believes it is immediately necessary to protect themselves against the use of unlawful force by another person.

Crucially, there is no duty to retreat codified in a simple use of force as a justification defense. Therefore, if a criminal defendant punched someone (presumably not deadly or creating a serious bodily injury) there is no duty to retreat. If that same defendant, instead, used deadly force (such as a gun), they would be required to show that they attempted to retreat, an exception applied, or they had no legal option but to use deadly force.