This attitude led to the president’s decisive intervention — a six-page memo designed to impose time and resource limitations on a reluctant military. Generals, of course, are not always right, as President George W. Bush discovered in the early years of the Iraq War. But are we supposed to be reassured that a president, of no proven military judgment, driven at least partially by political calculations, imposed a split-the-difference approach, only loosely related to actual need or analysis? A temporary increase of 30,000 troops coupled with a withdrawal deadline, it now seems, was an arbitrary compromise, not a fully developed military strategy. The armed forces were told to salute and make do. No wonder an Obama adviser complained to Woodward that the strategic review did not “add up” to the president’s eventual policy.

Woodward’s book is genuinely reassuring about Obama in some areas — his general commitment to fighting terrorism, his focus on the possibility of nuclear terrorism, his understanding of the threat originating in Pakistan. But the more we know about Obama’s views of the Afghan War, the less confidence he inspires. Is there a historical precedent for an American president, in time of war, hoping to convey an impression of studied, professorial ambivalence about the war itself? Is it possible to imagine Franklin Roosevelt or Harry Truman purposely cultivating such ambiguity?

Yes, President Obama has sent more skilled, well-led troops to Afghanistan. But he has also created a strategic challenge for America. Our enemy is patient and determined. Our president, by his own account, is neither.