Under what condition is a person criminally responsible as a party to an offense?

A person is criminally responsible as a party to an offense when the offense is committed by their own conduct. This principle reflects the foundation of criminal liability, which holds individuals accountable for their direct actions that lead to the commission of a crime. Personal conduct directly implicates an individual in wrongful behavior, establishing a clear link between the act and the person. Consequently, when someone engages in criminal conduct, they can be prosecuted for that offense.

The other conditions presented do not fully encompass the criteria for criminal responsibility. For instance, while a person may also be implicated if they facilitate or encourage another's criminal actions, that is not solely based on personal conduct. Additionally, the lack of planning in some offenses does not exempt a person from liability; rather, personal involvement is critical in determining accountability. Lastly, while proof beyond a reasonable doubt is essential for a conviction in court, it relates to the standard of evidence required for culpability rather than the fundamental nature of personal responsibility in the commission of an offense.