War Powers for Dummies
"The Constitution gives Congress the sole power to declare war, but it also says that the president is commander-in-chief of the armed forces. So the way presidents have usually responded is simply by not bothering to ask for a declaration of war when they want to begin a military undertaking. In fact, the last time Congress declared war was in 1942, when it did so against Romania, or as it was known then, Rumania. There were six separate war declarations in World War II, one for each country in the Axis (see here for more detail on our 11 war declarations; h/t Garance Franke-Ruta). Many of our biggest wars, including Korea, Vietnam, and Iraq, had no formal declaration of war."
