<P> The United States insisted on maintaining the traditional rights of ships registered in neutral countries and protested strongly against American ships being intercepted or sunk: the British seized American ships for supposed violations, while the Germans sank them--often without warning, in violation of international law that said sailors must be allowed an opportunity to reach their lifeboats . After several violations, Germany stopped this practice but in early 1917 she decided to resume unrestricted submarine warfare, in the hope that this would starve out the British before the Americans could make any effective military retaliation . </P> <P> The British Royal Navy successfully stopped the shipment of most war supplies and food to Germany . Neutral American ships that tried to trade with Germany were seized or turned back by the Royal Navy who viewed such trade as in direct conflict with the Allies' war efforts . The strangulation came about very slowly, because Germany and its allies controlled extensive farmlands and raw materials . It was eventually successful because Germany and Austria - Hungary had decimated their agricultural production by taking so many farmers into their armies . By 1918, German cities were on the verge of starvation; the front - line soldiers were on short rations and were running out of essential supplies . </P> <P> Germany also considered a blockade . "England wants to starve us", said Admiral Alfred von Tirpitz, the man who built the German fleet and who remained a key advisor to the Kaiser Wilhelm II . "We can play the same game . We can bottle her up and destroy every ship that endeavors to break the blockade". Unable to challenge the more powerful Royal Navy on the surface, Tirpitz wanted to scare off merchant and passenger ships en route to Britain . He reasoned that since the island of Britain depended on imports of food, raw materials, and manufactured goods, scaring off a substantial number of the ships would effectively undercut its long - term ability to maintain an army on the Western Front . While Germany had only nine long - range U-boats at the start of the war, it had ample shipyard capacity to build the hundreds needed . However, the United States demanded that Germany respect the international agreements upon "freedom of the seas", which protected neutral American ships on the high seas from seizure or sinking by either belligerent . Furthermore, Americans insisted that the drowning of innocent civilians was barbaric and grounds for a declaration of war . The British frequently violated America's neutral rights by seizing ships . Wilson's top advisor, Colonel Edward M. House commented that, "The British have gone as far as they possibly could in violating neutral rights, though they have done it in the most courteous way". When Wilson protested British violations of American neutrality, the British backed down . </P> <P> German submarines torpedoed ships without warning, causing sailors and passengers to drown . Berlin explained that submarines were so vulnerable that they dared not surface near merchant ships that might be carrying guns and which were too small to rescue submarine crews . Britain armed most of its merchant ships with medium calibre guns that could sink a submarine, making above - water attacks too risky . In February 1915, the United States warned Germany about misuse of submarines . On April 22, the German Imperial Embassy warned U.S. citizens against boarding vessels to Britain, which would have to face German attack . On May 7, Germany torpedoed the British passenger liner RMS Lusitania, sinking her . This act of aggression caused the loss of 1,198 civilian lives, including 128 Americans . The sinking of a large, unarmed passenger ship, combined with the previous stories of atrocities in Belgium, shocked Americans and turned public opinion hostile to Germany, although not yet to the point of war . Wilson issued a warning to Germany that it would face "strict accountability" if it sank more neutral U.S. passenger ships . Berlin acquiesced, ordering its submarines to avoid passenger ships . </P>

To prepare the country for world war 1 what became an early focus