There is one question above all others to which historians return again and again. Could this catastrophe have been avoided? In trying to answer that question, historians have tried to tackle smaller chunks of it. Here is a sampling of the questions that historians have asked.

Did the monarchical governments of Germany, Austria, and Russia impede a rational solution of complex problems by means short of war? If so, how? Is democratic government naturally more peaceful than monarchical or authoritarian government?

Did the military staffs and their plans, especially in central and eastern Europe, get out of hand?

What part did the widely accepted beliefs of the day play in the coming of the war? The elites in all countries saw war as a legitimate instrument of national policy. Many people accepted ideas of competition, rather than cooperation, between countries, races, and social classes.

European social and political systems were out of joint with the basic realities, so perhaps a great upheaval would have come in any event.

What did domestic crises add to the decision for war? Germany’s established rulers faced political problems in dealing with the rise of the SPD and Center parties; the Austrian rulers faced crises over domestic reforms and South Slav resistance to “Magyarization; Russian rulers feared that a failure to support Serbia would revive the revolutionary forces of 1905. Did the struggle for more responsive government in Germany, Austria, and Russia mean that all were headed toward revolution even without the First World War? Did decision-makers choose war as a way of holding off or resolving domestic problems?

What role did international problems play in the decision for war? The key problems were the rightful place of Germany in Europe, the inability of anyone in central and eastern Europe to formulate a constructive solution to the problems of nationalism in multi-national and multi-ethnic states.

Was the war the product of human errors, which could have been avoided or corrected if better people had been in power, or was it the product of profound causes, which better people might have delayed but could not have prevented from boiling up at some point?

To these questions I would add one more. What lessons, if any, do the answers to these questions have for our own time?