In WW1 Wilson tried to stay out of the war and stay neutral, supplying both sides. But Germany was not happy with the US supplying the Allies, so on January 31, 1917, Germany announced that they would commence the renewal of unrestricted submarine warfare in the Atlantic. They sunk an unarmed ship, called the Lusitania, a British passenger liner, which killed 128 Americans. The Germans also tried to get Mexico to invade the US to distract them, called the Zimmermann Telegram.
