General David Petraeus's fatal flaw: not the affair, but his Afghanistan surge

More than three years ago, I sat in an overflow room in Washington, DC's Willard Hotel listening to General David Petraeus explain (pdf) how the only solution for the failing war in Afghanistan was a "comprehensive counterinsurgency (COIN) strategy", modeled after the one that had allegedly achieved so much success in Iraq.

Petraeus handing over to Allen

Petraeus's speech came at the annual meeting of the Center for New American Security, a DC-based thinktank that had become a locus of COIN thinking in DC. And Petraeus was at the peak of his power and acclaim – heralded by both Democrats and Republicans as the man responsible for saving the Iraq war.

The four-star general's in-depth powerpoint presentation (pdf), with its discussion of securing and serving the population, "understanding local circumstances" separating irreconcilables from reconcilables and living "among the people" was the apogee of COIN thinking, which dominated national security debates in Washington in 2008 and 2009. But, like Petraeus's career, COIN and its usefulness as a tool for US militaryplanners now lies in tatters.

With last week's revelations that Petraeus was having an affair as director of the CIA with his biographer Paula Broadwell, this tawdry story is likely to become the most glaring black mark on Petraeus's career. But while his behavior was reckless, arrogant and, frankly, just plain stupid, it's ironic that Petraeus is likely to be remembered more for that one personal act rather than his most grave professional mistake – namely, that same counter-insurgency strategy in Afghanistan for which he was one of Washington's most influential proponents.

The event at CNAS was the quintessential example of the blinders and hubris that were so pervasive among COIN boosters and, in particular, Petraeus. They were convinced that the surge in Iraq and the use of counterinsurgency tactics there had turned the tide. But as we know now – and should have even been aware then – the reality was far more complicated. More