R v. Hasan is a significant legal case in the context of duress, where the defendant claimed he acted under threat to his life, influencing the court's understanding of duress as a defense in criminal law. This case is pivotal because it explores the boundaries of when duress can be successfully argued and highlights the importance of immediacy and proportionality in assessing claims of coercion. The ruling clarified that the defense of duress cannot be used for all crimes and is limited by specific circumstances.