I'll take a stab...
...This question is quite subject to the varying political complexion of individual historians treating the period.
What seems to be beyond argument is that the explosion in technological and industrial development throughout the 19th century tended to result in the creation of vast stockpiles of increasingly lethal weaponry. This, in conjunction with the population explosion in Europe throughout that period, had the effect of making warfare disastrously expensive and destructive. Bigger, better fed, more literate populations enabled the creation of vast conscript armies, armed with weaponry of ever increasing range, accuracy, and lethality.
These trends continued into (and through) the 20th century, culminating in the World Wars, the development of nuclear weapons, and all the other attendant facts of life we have existed under ever since.
There are definite currents of historical analysis that contend that capitalist classes, most characteristically arms manufacturers, tended to encourage these trends (by way of their ever increasing political clout) as a means of enriching themselves.
The extent to which these groups were a cause (or merely a symptom) of militarism is certainly not one that can be resolved in a school term paper.