Germany also made a secret offer to help Mexico regain territories lost in the Mexican–American War in an encoded telegram known as the Zimmermann Telegram, which was intercepted by British intelligence. Publication of that communique outraged Americans just as German U-boats started sinking American merchant ships in the North Atlantic. Wilson then asked Congress for "a war to end all wars" that would "make the world safe for democracy", and Congress voted to declare war on Germany on April 6, 1917.