That is an interesting observation, and one I've heard made by smarter people than I.
Historic events should never be directly applied to current situations in my opinion. Instead, historical events should be used as precidents in forming models of international relations. This is very much a case when it comes to WWI vs. WWII.
People use WWI as a historic example of a situation that would best be explianed with the "Spiral model". According to this model, none of the participants were all that interested in losing millions of young men, but were compelled to do so out of fear and confusion. If that fear and confusion could be lessened, you could avoid war. Here's how it works: Side a begins a military buildup because it sees side B as a threat. Side be recipricates what it sees as overt agression by side A. Rinse, repeat until at some point, someone gets shot, and then it's on (Bring it Ivan!) In this model, none of the states are truly agressive, instead they are all seeking security.
WWII on the other hand is a favorite of the Deterrence Model. This model suggests that because we can never truly know the intentions of those around us, we should make sure that they can not pose a threat. We do this by maitaining a strong military, and countering any of their moves with moves of our own. We make sure that at any time they will not have the means to defeat us militarily, and therefore they will not try.
Of course you you can see that following one model (deterrence) helped set up the first situation. And the other model (spiral) set up the second situation.
It is so increadibly difficult to know which way things will turn. You need to look at each situation seperately, and try to best understand the correct model to use. Events are overdetermined. And adding to this are things like asymetrical threats and WMD. So you can see that those who use historic examples to justify or refute any current policy or action are usually (not always) just shooting from the hip. Unless of course they offer soemthing more to move their positions foreward.
-Sikboy
