Quote from : The Revolution in Warfare Book

The history of ancient Greece showed that, in a democracy, emotion dominates reason to a greater extent than in any other political system, thus giving freer rein to the passions which sweep a state into war and prevent it getting out—at any point short of the exhaustion and destruction of one or other of the opposing sides. Democracy is a system which puts a brake on preparation for war, aggressive or defensive, but it is not one that conduces to the limitation of warfare or the prospects of a good peace. No political system more easily becomes out of control when passions are aroused. These defects have been multiplied in modern democracies, since their great extension of size and their vast electorate produce a much larger volume of emotional pressure.