1. British Blockade: Ger. economy sinks, no food or supplies brought in, Navy useless, led to U.S.W.
2. Slow breakdown of German allies, especially A-H, only in it for spoils if victory
3. Morale effect of US entry into war, increased Allies, decreased Germans
4. US entry led to 1918 offensives, last desperate gambles
5. British control of the seas: led to U.S.W. and American entrance, blockade set up