In physics, it's known as Newton's third law of motion: For every action, there is an equal and opposite reaction.
The principle of reciprocal action, however, has applications beyond science. It's present in all sorts of human endeavors, not least in military conflict.
Phillip Carter, a Slate contributor and Iraq war veteran, has written that the United States has run through at least six successive strategies in Iraq. Beginning with "shock and awe," American strategy has both provoked responses and evolved from the reactions of Baathists, al-Qaida-inspired jihadists and Shiite militias.
Now even fierce critics of the Iraq war are grudgingly acknowledging that the latest strategy the surge is making progress, improving security on the ground in Iraq. The insurgents will have a reaction. In fact, the horrific bombings last week in northern Iraq that killed more than 400 people are an indication of what is to come.
Thanks to the Internet and the global democratization of communication, our enemies in Iraq can read our press and polls with greater ease than any adversaries in history. The insurgents aren't just casual observers of American information. As groups like the SITE Search for International Terrorist Entities Institute, www.siteinstitute.org, demonstrate, they are media-savvy consumers and producers.
As such, they realize the importance of Sept. 15. That's the date when Gen. David Petraeus gives his report to Congress a report that will determine the future of U.S. involvement in Iraq. And even if our enemies in Iraq were to exhaust their ranks over the next four weeks in suicide attacks, just as the Viet Cong did during the Tet Offensive, they know that the spectacle of bombs going off as Petraeus speaks on Capitol Hill will be enough to render the general's words moot just as the Viet Cong did during the Tet Offensive.
"I only served in Iraq for one year," Capt. Craig Olson wrote to me recently, "operating in the Triangle of Death south of Baghdad, up north during the Battle of Tal Afar, and during the first-ever provincial and national elections as the Intelligence Officer for a Cavalry Squadron in the 3rd Armored Cavalry Regiment out of Fort Carson, Colo."
Olson is a West Point graduate and Army Ranger with two graduate degrees. He has recounted his experiences in Iraq in a book, "So This is War," www.sothisiswar.com.
"To my surprise," he told me, "I left a nation full of upbeat and hopeful soldiers to come home to a jaded and dejected public who was about to call it quits. Ironically, our internal anti-war movement was serving to deepen the chaos and increase the danger for our soldiers as we totally lost the trust of the Iraqi populace. The only way to find an IED or to stop a suicide bomber is to gain information from the locals who trust we will protect them, and that trust faded away as quickly as the anti-war drumbeat heated up back home."
I quote Olson not to stifle dissent about the Iraq war, to impugn the patriotism of American citizens who challenge the U.S. role in Iraq or to suggest that blind obedience is necessary while Americans are engaged in military conflicts. I quote him to demonstrate that in war, every action even well-intentioned, patriotic ones has a reaction.
Steven Levitt is one of the authors of the immensely popular book "Freakonomics: A Rogue Economist Explores the Hidden Side of Everything." He made a stir recently on the New York Times blog he shares with co-author Stephen Dubner by asking the question, "If you were a terrorist, how would you attack?" then providing his own answers and requesting that readers offer theirs.
Levitt's post is a controversial demonstration of James Surowiecki's "Wisdom of Crowds" theory. If wiki-terrorists could explore and expose the nation's vulnerabilities in theory, it might offer practical help to homeland security officials trying to anticipate and deter terrorist attacks.
It doesn't take a physicist, an intelligence officer or an economist to anticipate that the action of making Sept. 15 such a climactic date invites a lethal reaction from our enemies.