system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why hasn't the U.S. government issued a formal declaration of war in any conflict since WWII?
gpt
Congress has to make a vote on it, making it harder to achieve. Also the laws of wars, as established after World War II, are very strict and would leave the US government open to litigation (for war for any reason except self-defense). Now the US has something called Authorization of Use of Military Force (AUMF) instead that congress votes on, but the president can do a lot besides that.