Wilson insisted on neutrality and minimized wartime preparations to be able to negotiate for peace. After the British ship "Lusitania" was sunk, with over 100 American passengers drowned, Wilson demanded for German submarines to allow passengers and crew to reach their lifeboats before ships were sunk. Germany reluctantly agreed, but in January 1917, it decided that a massive infantry attack on the Western Front, coupled with a full-scale attack on all food shipments to Europe, would prove decisive. It realized the resumption of unrestricted submarine warfare almost certainly meant war with the United States, but it calculated that the U.S. Armed Forces would take years to mobilize and arrive, when Germany would have already won. Germany reached out to Mexico with the Zimmermann Telegram, offering a military alliance against the United States, hoping the United States would diverge most of its attention to attacking Mexico. London intercepted the telegram, the contents of which outraged American opinion.