This article examines the historical and legal dimensions of war and peace within the Polish constitutional framework, focusing primarily on the 1997 Constitution. The author situates contemporary regulations in a broad historical context, tracing the evolution of parliamentary oversight from the 16th-century “nobles’ democracy” through the partition era (1795–1918) and 20th-century constitutional models. Central to the study is Article 116, which vests the primary authority to declare a state of war in the Sejm—a role derived from both ancient traditions and the traumatic wartime experiences of the 20th century. The analysis extends to the legal consequences of such declarations, including martial law, states of emergency, and the restriction of civil liberties. Furthermore, the paper critically evaluates the practical application of these provisions in the context of Poland’s post-1989 foreign policy, specifically its participation in military interventions in Afghanistan (2002–2021) and Iraq (2003–2011). The author argues that while the 1997 Constitution reflects democratic ideals, the use of “armed conflict” as a legal designation has created a controversial loophole for military operations conducted without a formal declaration of a “state of war”. Finally, the article addresses Poland’s obligations within NATO and its response to contemporary security threats, such as the Russian aggression against Ukraine.