How does universal jurisdiction allow national courts to prosecute certain international crimes?

Under international law, universal jurisdiction allows national courts to prosecute specific, grave international crimes regardless of where the offense occurred or the nationality of the perpetrator or victim. This principle serves as a vital mechanism for accountability, reflecting the ethical imperative that certain atrocities are so heinous they offend humanity as a whole and should not go unpunished.12

While national legal systems typically restrict jurisdiction to crimes committed within their territory or by their own nationals, this rule is relaxed for war crimes, crimes against humanity, and genocide. Historically, piracy on the high seas was the primary example of a universal crime; however, the list expanded in the 20th century to include torture and other severe violations.21

For certain offenses, such as grave breaches of the Geneva Conventions, international treaties may impose a duty to prosecute or extradite offenders under the principle of aut dedere aut judicare (either adjudicate or extradite).2