In the June 13 PostEverything commentary, “The cost of a job half-done” [op-ed], John Nagl wrote that he and his friends did not fight in Iraq only to have the administration provide al-Qaeda with a new lease on life by declining to leave a long-term assistance force in Iraq. His understandable claim is misguided, as is his hope that the United States will not make the same mistake in Afghanistan.

Mr. Nagl and his friends fought and died because the George W. Bush administration invaded Iraq under false pretenses, did not send enough troops, destroyed the Iraqi state and placed Nouri al-Maliki in power after a contested 2006 parliamentary election despite his evident sectarian tendencies.

Al-Qaeda was not in Iraq until we invaded. Moreover, by diverting our attention from Afghanistan to Iraq, we missed the golden moment to eliminate the Taliban, instead allowing it to regroup and ensuring that it will have a role in Afghanistan when we leave.

Many of us who served in Vietnam, where more than 10 times as many Americans died as in Iraq, faulted not the Nixon administration for getting us out but rather the Johnson administration for getting us in. The veterans of Iraq should direct their frustration toward the right target.

Lawrence J. Korb, Washington

The writer is a senior fellow at the Center for American Progress.