This week's NATO summit in Chicago was expensive in the short run for the United States as its host, and costly in the long run as the nation remains the lead force in Afghanistan.
The summit's main topic was the route by which NATO members will leave Afghanistan. The war there has been going on since 2001, when the United States intervened after the 9/11 attacks.
The U.S. objectives were to drive out al-Qaeda, which carried out the attacks; to unseat the Taliban, the Islamist group that ruled Afghanistan and hosted al-Qaeda leaders, and to try to reshape Afghanistan so it would not allow the conditions that led to 9/11 to recur.
Afghanistan was a distant venture for NATO. Yet the alliance has maintained a credible presence. The United Kingdom, France, Germany, Canada, and Italy have provided troops and other support.
In recent years, exasperation with the diminishing prospects of a favorable outcome in Afghanistan have created growing sentiment for NATO countries to end their involvement. The sources of disaffection include disgust at the corruption and inefficiency of President Hamid Karzai's government, despair at the challenges of training Afghans to fight the war, anger at growing attacks by Afghan soldiers on NATO troops, and the financial cost of engagement.
Pain from the cost has grown as NATO countries' domestic economies have weakened. The cost of preparing Afghan forces to replace NATO troops is estimated at more than $4 billion a year. President Obama hoped to get pledges from NATO members at the summit to cover at least half of that amount, but he does not appear to have done so.
At the summit, France's new president, Francois Hollande, restated his campaign pledge to withdraw his country's combat forces from Afghanistan this year. Mr. Karzai's presence was largely a symbolic irritant.
Pakistan's president, Ali Asif Zardari, came to Chicago to press Mr. Obama for an apology for the 24 Pakistani troops who were killed in a U.S. air raid last November. He demanded a higher price to permit supplies for NATO forces in Afghanistan to enter through Pakistan.
Americans who oppose the Afghanistan war, NATO, and the Pentagon budget demonstrated in Chicago. Police kept protesters under control, but batons were wielded and arrests marred the summit.
The most promising aspect of this week's summit was the President's declaration that the timetable for withdrawal from Afghanistan is "irreversible." The war's ending will be uncertain, but what's most important is that it ends.