Median figures for military and civilian deaths:

World War I ... 17,500,000 dead
World War II ... 50,000,000 dead

It's not just the beginning that we have to worry about, it's the unforeseen end (if there is one.)

In Europe, WWI was sparked by the assassination of one man in a small country, in a region as volatile as the Middle East is today. Within four years, it grew to a conflagration that consumed over 17 million people, then erupted again 20 years later with even more tragic consequences.

For the United States, WWII began with 2,408 dead and ended with over 400,000 military dead (and no civilian dead within U.S. borders, except for an unlucky few).

Statistically, we can argue that 12 U.S. military dead per day, or 60 per week, or 600 per year, or however many more in (?) years, are only a few good men and women. But each and every life lost on all sides is irreplaceable to a multitude of mothers, fathers, wives, husbands, and children.

And if those civilians have unwisely chosen the wrong side, many of them will lose their lives also. Perhaps if we don't count civilian casualties any more, they won't matter.

Once lit, and once the flame is fanned, who knows where a war will lead us?

It's a rope with a noose at each end.

Some excellent points -- but it is worth emphasizing some important differences. The Balkans in 1914 may indeed have been "as volatile as the Middle East is today", but it was their position astride the fault lines between rival Great Powers that allowed an assassination to touch off world war.

Without the USSR, the risks of Western interventions in the Middle East appear more comparable to those incurred by the British in their colonial adventures -- not insignificant, of course, but not really in the same class as all-out war between Great Powers or their proxies (this Moscow Times article may also be apropos).

It will be difficult to find historical examples that fit the present situation in the Middle East exactly. Every war is different in its circumstances and consequences, but I wonder if any have turned out as planned.

Clearly the Middle East is a critically strategic area: would the United States be involved otherwise? And having been there twice in less than 15 years, I imagine we have captured the attention of Russia and China, neither of whom are all that distant, both of whom are far more familiar with (and more hardened to) the numbers of war.

Throw in Saudi Arabia, Israel, Jordan, Syria, Turkey (and the Kurds), Iran, Afghanistan, Pakistan, and even India. Spice things up with Judaism, Christianity, and Islam. Add prodigious quantities of weaponry from all countries previously mentioned, and I think the region can match, if not exceed, pre-WWI Europe for complexity.

It is the sheer unpredictability of war that should make us extremely wary of conducting one. We simply do not know what might happen, any more than mankind knew in 1914 or 1939. The only sure things we can plan for are more death and destruction. I only hope there a limit to how much we can afford to suffer (or inflict).