In the Summer issue of Harvard’s journal International Security, Dominic D.P. Johnson and Dominic Tierney published an interesting article proposing “the Rubicon theory of war” (summary | pdf). As Julius Caesar’s crossing of the Rubicon river has come to symbolize a point of no return, the authors explain how the path to conflict reaches the point of no return once people perceive war to be imminent. Leaders experience a sudden shift in mentality from deliberation to implementation, decreasing the chance of a peaceful resolution. 

Experimental psychology has demonstrated that the act of making a decision can bring about a state of overconfidence, irrational optimism, and closed-mindedness, limiting rational thought and the ability to compromise.  If leaders make this psychological shift before war has become inevitable, narrower vision and lack of deliberation may contribute to the outbreak of war.

Their case study on World War I is a bit less relevant to current conflict contexts, but an interesting exercise would be to test the authors’ hypothesis with civil wars and internal conflicts. Our guess is that overconfidence is a “potent and pervasive cause of war” in these contexts as well.