Claim: The United States has never officially declared war since World War II, despite fighting in Korea, Vietnam, Iraq, and Afghanistan

The claim is true: the United States has not officially declared war since World War II. This is supported by multiple reputable sources, including historical records from the U.S. Senate and encyclopedic entries. These sources confirm that the last formal declarations of war occurred during World War II, with subsequent military engagements authorized through different means. Critics may argue about the nature of military actions post-WWII, but this does not change the fact that no formal declarations have been made since then. The models diverge sharply — treat this as higher-uncertainty. Perplexity comes in highest (100%), while Gemini is lowest (50%). OpenAI expresses higher confidence than Gemini on this claim. While the evidence strongly supports the claim, some may argue that the U.S. has engaged in military actions that could be considered equivalent to declarations of war. However, these arguments do not change the factual basis that formal declarations, as defined by Congress, have not occurred since World War II. The distinction between declarations and authorizations for military force is crucial and is upheld by the evidence provided, which consistently points to the absence of formal declarations in the post-WWII era.