
Traditionally, Americans have viewed war as an alternative to diplomacy, and military strategy as the science of victory. Today, however, in our world of nuclear weapons, military power is not so much exercised as threatened. It is, Mr. Schelling says, bargaining power, and the exploitation of this power, for good or evil, to preserve peace or to threaten war, is diplomacy - the diplomacy of violence. The author concentrates in this book on the way in which military capabilites - real or imagined - are used, skillfully or clumsily, as bargaining power. He sees the steps taken by the US during the Berlin and Cuban crises as not merely preparations for engagement, but as signals to an enemy, with reports from the adversary's own military intelligence as our most important diplomatic communications.
His books "The Strategy of Conflict" and "Arms and Influence" are essential reading. They were influential bringing game-theory into the nuclear strategy, disarmament and foreign policy.
Once the armies were assembled it was going to be
impossibly difficult to move them all back so they got
put into action instead.
I read a more subtle theory in the book "Arms and Influence" by Thomas C. Schelling [1].In short, at the start of WW1, the Russians had two plans available: A plan to mobilise against the Austro-Hungarians only, and a plan to mobilise against them and the Germans at the same time.
But if they went for the Austria-Hungary-only plan, they'd be extra-vulnerable to German attack. After all, the troops and trains are all in the wrong place!
So although they were _mostly_ worried about Austria-Hungary, they were moderately worried about Germany, so they went with the mobilise-against-both plan. And as soon as Russia started massing troops at the German border, what could Germany do except respond in kind? Hence there was an escalation to war despite the fact neither side would benefit from it.
In other words: The logistics played a part, but it wasn't _just_ using the troops because they're here now - the logistics forced the Russians to choose between two bad options, forcing them into a choice that would inevitably trigger the escalation to war.
[1] https://books.google.co.uk/books?id=TX_yAAAAQBAJ&pg=PT161&lp...