Nor is the rationale flawless. It is possible to discover various statistical correlations among democracy and war and peace, depending on how they are defined and in what time frames. The chief pitfall in such social-science exercises is in weighing something such as, for example, the Mughal Campaign in Transoxiana, 1646-47, against something like, for example, World War II. Generally, a straightforward historical approach is better. And what does it show?
Even without reference to the case of a democracy that, finding self-defense insufficient justification and retaliation an insufficient end, makes war on a non-democracy so as to make the non-democracy a democracy, the postulate on which the president has in all good faith chosen to rely is contradicted by inconvenient fact.
Germany, the primary instigator of World War I, was a democracy. Although party governance weakened immediately before the war, it did so according to the popular will. When hostilities broke out, power flowed back to the Reichstag as a result of its increased belligerency in reaction to the threat of, perhaps ironically, nondemocratic Russia. Democratic Italy joined the entente because it had been spoiling for a fight to wrest South Tyrol from Austria. Extending its northern defenses to the natural Alpine barrier was obviously in Italy's interest, and popular sovereignty acted not as a break on war for this purpose but as a stimulus.
Less a democracy but a democracy nevertheless, Japan saw its parliamentary government wax and wane in the decades before World War II, losing eventually to the militarists but resurging as late as 1937 almost to regain control, with the Meiji Constitution unrepudiated and in force throughout the war.
What is one to make of the many 19th century colonial conquests on the part of democratic European powers? What is one to make of the Mexican and Spanish-American wars, in which, on the flimsiest pretexts, the United States, the leading democracy in the world, moved to war? And, four score and five years after the American founding, the most destructive war in American history arose entirely from within, in belated and necessary fulfillment of the Constitution and the Declaration of Independence, documents unexcelled as the guide stars of democracy itself.
Immediate counters to these examples might be that Prussian democracy is an oxymoron, Italian democracy was more feeble then than it is even now, the Japanese had made only a shadow play of Western constitutionalism, colonial conquests don't count because they had begun before the European democracies matured and were continued out of habit (oops, there goes the Congo; we did it again). And as for the United States, well, the Mexican War had something to do with Texas, the Spanish-American with the Maine, and at the time of the Civil War, not a single woman was able to vote and a large portion of the population was enslaved.
But such attempts at explaining the complexity of a democracy's relation to war — young democracies are ferocious, old ones serene; the extent and/or speed of economic development predisposes a democracy one way or another in regard to war and peace; as do limitation or extensions of the franchise; etc. etc. — tend to founder because the sample is simultaneously too varied and too small to produce valid rules.
And that is just the point. It isn't that democracies are too old or too young or too fat or too thin, but that none is perfect and that, therefore, all are subject to forces that may override the theoretical peacefulness of representative governments. Even perfect democracies, which have never been and will never be, cannot offer the kind of Pax Democratica that the United States now seeks to construct among a group of states that are famous for their immunity to liberal governance.
Other than Israel, the major countries of the region that are the most democratic are Turkey, Pakistan, Lebanon and Kuwait. If democracy in Turkey and Pakistan could be drawn as a horse, it would have to have a soldier in the saddle. In Lebanon, it would have a Syrian in the saddle.
And the more Turkey and Pakistan approach the genuine democracy to which American policy would direct them, the more Islamist they will become and the more they will want to do exactly the opposite of what we desire. The more Kuwait democratizes too, the more Islamist it becomes. In the 2003 elections, only 20% of contested seats went to neither traditionalists nor Islamists, and of late the democratically nascent governments of Iraq and Kuwait have had to erect a fence along their border to prevent Kuwaiti youth from crossing to join the insurgency.
Not only does the U.S. expend a great deal of effort to usher politically impure states into a form of popular sovereignty that will not stop them from acting inimically to our interests, but in distancing itself from authoritarian states that are willing to work with us, it forgoes potentially critical advantages. For the pleasure of displaying our virtue, we may someday suffer innumerable casualties in a terrorist attack that a compromised state might have helped us to prevent.
In foreign policy, carelessness and confusion often lead to tragedy. Thus, a maxim chosen to guide the course of a nation should be weighed in light of history and common sense.
Or is that too much to ask?
Mark Helprin is a senior fellow of the Claremont Institute. His novels include "A Soldier of the Great War" and "Winter's Tale." A version of this article will appear in the forthcoming issue of the Claremont Review of Books.