The German government announced unrestricted submarine warfare against ANY ship sailing into Allied waters would be subject to surprise attack. Along with the German sabotage of Black Tom island powder magazine in 1916, the sinking of the Lusitania with American citizens onboard, and the Zimmerman telegram (German foreign secretary) that encouraged Mexico to ally with Germany and Mexico would win bad the former Mexican territory in the US South West, lead President Wilson to call for war. There were additional reasons, but I feel these were the Big Four.
U Boats were causing havoc on the trade routes between the US and Europe by destroying merchant ships. One of the biggest factors was the sinking of the Ocean Liner "Lusitania" by German UBoats, of the 139 US Citizens on board 128 were killed. Also, when Germany began a Submarine Campaign against Britain President Wilson had previously stated he would hold Germany responsible if that were to occur.
unrestricted submarine warfare
Sinking civilian ships without warning (un-restricted submarine warfare).
In WW1, the German policy of unrestricted submarine warfare irritated neutral nations such as the United States and eventually helped public opinion to support the US entry into the war. In WW2 the German policy of unrestricted submarine warfare in the Atlantic irritated nominally neutral nations such as the United States and provided a rationale for increasing US support of Britain and its allies. In WW2 the American policy of unrestricted submarine warfare in the Pacific probably contributed to the degradation of Japanese economic capabilities as the war progressed.
World War 1 introduced aerial warfare with airplanes and trench warfare
Germany announced an unrestricted submarine warfare campaign during World War I in early 1917. This strategy aimed to cut off supplies to the Allies by targeting military and civilian ships without warning. The decision contributed to the United States entering the war, as American vessels were also affected by these attacks.
Germany's submarine warfare was unrestricted. These attacks led to World War I.
unrestricted submarine warfare
Germany's unrestricted submarine warfare
unrestricted submarine warfare
Submarine Warfare
German submarine warfare
Because a German submarine was responsible for the sinking of the Luisitania, with many American citizens on board.
Germany hoped that submarine warfare would lead to war.
unrestricted submarine warfare
WW1 introduced submarine warfare, tanks, chemical warfare, and aerial combat. Man's history already knew battleship warfare from Tsushima in 1905; and massed land warfare consisting of infantry. WW2 REFINED submarine warfare, tanks, and aerial warfare; chemical warfare was outlawed by treaty.
A submarine sunk the liner 'Lusitania'. Many Americans died. USA was horrified, declared war on Germany.
Germany's unrestricted submarine warfare