The seemingly universal consensus that existed mere months ago that Afghanistan was a "necessary war" the West could not afford to lose has suddenly evaporated. Prominent liberals, centrists and conservatives are coming out in droves to proclaim our goals too lofty and the chances of success too low to justify the high cost in blood and treasure.

If, as now seems inevitable, we leave Afghanistan without finishing the job-whatever that job might be-there will of course be geopolitical consequences. These are being debated at great length elsewhere. Atlanticists, however, have an additional concern: what will the impact be on NATO?

Shortly after taking office in January 2004, then-NATO Secretary General Jaap de Hoop Scheffer declared "Our first, and immediate priority is to get Afghanistan right. We cannot afford to fail." He continued, "If we fail in Afghanistan-if we do not meet our commitments to the people of that country to help them build a better future-then w...