Already the annual cost of America’s errand in Afghanistan is larger than that country’s GDP. U.S. success depends on Afghans perceiving the central government as legitimate, which they will not do for at least five more years. Americans, led by a commander in chief whose heart is not in it, will not sustain the years of casualties and other costs necessary to create self-sufficient Afghan security forces beneath a corrupt regime.

On July 24, 2008, in Berlin, Obama stressed the need to “defeat the Taliban.” Then, however, he spoke as a “citizen of the world,” not as president. Now he is being presidential by reconsidering some implications of the politically calculated rhetoric that helped make him president. He is rightly ignoring those who cannot distinguish thinking from dithering.

President Woodrow Wilson, looking censoriously at some nations to America’s south, reportedly vowed, “We will teach them to elect good men.” Whatever strategy Obama adopts, its success cannot depend on America teaching Afghans to do that. If he is looking for a strategy that depends on legitimacy in Kabul, he is looking for a unicorn.