The counterinsurgency doctrine assumes no such thing. As I hope I made clear in my piece, the impetus behind the surge is as much psychological as it is material. Clearing and holding Baghdad will provide time and resources to reconstitute the political and economic infrastructures of the capital, making the attractiveness and sustainability of any future insurgency that much less. Those who aren't encouraged to join in the attacks on coalition and Iraqi forces are at least cowed by the attackers to stay quiet and not inform on such riffraff. But civil incentives -- turning back on basic utilities, expanding a dire job market, etc. -- fills the vacuum in which Al Qaeda now bombinates. Zarqawi understood this all too well: In one of his many pronouncements before his not-timely-enough death, he foresaw that if civil war were averted in Iraq (with Al Qaeda presumably rushing in a such an ideal moment to cobble together its caliphate), his forces would have to revert to a new base of operations -- namely, Syria. Zarqawi did little accounting for the sheer figures of his terrorist army because he knew that these fluctuate with disillusion and chaos in whatever host country the army established itself. So it's not a matter of squashing individual terrorists as it is of killing off their blood supply.

The commenter is also wrong to say that the U.S. presence is directly correlated to levels of violence in postwar Iraq. Generally, where coalition numbers have increased in a region, the violence in that region has gone down. Also, there is every indication that a phased or categorical withdrawl of U.S. soldiers would give way to ethnic cleansing or genocide; surely a set of circumstances that would up the frequency of "violent acts."

As it stands, our presence may be the only stopgap between a sclerotic and faction-riven failed state and perhaps the bloodiest regional war the Middle East has ever known.