While there is no statistical evidence that wars break out any more often in late summer than in other seasons, the world was torn apart twice during the 20th century: in early August 1914, and then again on Sept. 1, 1939, when Nazi Germany invaded Poland. Maybe it is the effects of the heat, or the sense of urgency to do something before the cold of winter; but nonetheless, we've also seen a lot of late-summer violence the last few decades.
Saddam Hussein invaded Kuwait on Aug. 2, 1990, leading to an American-led air campaign and ground war in early 1991 that demolished the Iraqi army. On Sept. 11, 2001, 19 radical Islamic terrorists took down the World Trade Center complex and hit the Pentagon -- the worst foreign attacks on the continental United States since the British burned much of Washington, D.C., in 1814.
What can we learn from these dog-day cataclysms?
First, for all the rising prewar tensions, the general slaughter to follow was mostly unforeseen. Experts thought August 1914 would lead only to a war "over by Christmas" -- not 500 miles of trenches from the North Sea to Switzerland, and 8 million combat dead by 1918. Even after Hitler invaded Poland in a lightning strike, no one dreamed that more than 50 million deaths would follow.
Second, these late-summer bloodbaths usually followed from the initial impression of aggressors that they would face few consequences. After the Munich Agreement, Hitler had no reason to believe that gobbling up Poland would lead to a world war rather than more of the same appeasement. Saddam Hussein had no idea that the United States would react to a far-away border dispute by mobilizing a global coalition against him, and by bombing large swaths of Baghdad. Likewise, few imagined that nine years after 9/11, American troops would still be fighting in Afghanistan to keep the Taliban -- the former hosts of Osama bin Laden and al-Qaeda -- from returning to power.
In short, grand professions of peaceful intent in the face of global tensions, or even noble indifference to dictatorial aggression, instead ensure that war follows.
Finally, in the ensuing wars the United States lost thousands of soldiers when it was not well prepared -- and far fewer when it was. There was almost no American military in 1914 and little more when we declared war on Germany and Austria-Hungry in 1917.
America was once again woefully unarmed in 1939, when Germany started the European war, and not in much better shape when attacked by the Japanese in December 1941. As a result, in both of its victorious world wars the United States lost tens of thousands of troops.