(...) The worrisome misconception is that only shifts in relative power can destabilize a “balance of threat”. This falsely assumes that balanced situations, called equilibria, are inherently stable, which is actually often not the case. For illustration, consider the simple experiment of a circular vehicle flow (see http://www.youtube.com/watch?v=Suugn-p5C1M ): although it is apparently not difficult to drive a car at constant speed together with other cars, the equilibrium traffic flow will break down sooner or later. If only the density on the traffic circle is higher than a certain value, a so-called "phantom traffic jam" will form without any particular reason – no accident, no obstacles, nothing. The lesson here is that dynamical systems can easily get out of control even if everyone has good information, the latest technology and best intentions.
What if this is similarly true for the balance of threat? What if this equilibrium is unstable? Then, it could suddenly and unexpectedly break down. (...)
RISK OF WAR: WHAT, IF THE "BALANCE OF THREAT" IS UNSTABLE?
by Dirk Helbing (ETH Zurich)