Afghans are rioting, American soldiers are regularly murdered by their allies, the Taliban are hanging in, and civilian casualties in Afghanistan set a record last year. But a Pentagon spokesman assures us that "the fundamentals of our strategy remain sound."

He had to tell us because we wouldn't know it otherwise. In almost every respect, our venture in Afghanistan looks like a dismal, irredeemable failure. Year after year, we've been told that things are getting better. But lately, it's hard to take that claim seriously.

When Afghans erupted in rage over the careless burning of Korans at Bagram Airbase, the upheaval was not just about Muslim holy books. It was also about the grossly dysfunctional relationship between us and them—a product of the huge cultural gulf, our outsized ambitions and the irritant of our presence.

Afghanistan is a medieval country that we can barely begin to understand. Yet we presume that with all our money, technology, weaponry and wisdom, we can mold it like soft clay.

Things don't work so well in practice. Only one out of every 10 Afghans who sign up to join the army or national police can read and write. The military's desertion rate, an American general acknowledged last year, approaches a staggering 30 percent.

Many if not most Afghans have never heard of the 9/11 attacks. Even the deputy chairman of the government's High Peace Council told The Wall Street Journal he doesn't believe al-Qaida destroyed the World Trade Center.

So what can we expect ordinary people to think when they see the country overrun with armed foreigners who sometimes kill and injure innocent civilians? Or when they hear that those infidels are burning Korans?

The war in Afghanistan is now the longest in American history, and if hawks have their way, we'll be there for years to come. Alas, we have demonstrated the force of two things we already knew: Some mistakes can't be undone no matter how you try, and every guest eventually wears out his welcome.

In Afghanistan, we originally failed to make the needed commitment to destroy the enemy, because President George W. Bush was distracted by his eagerness to invade Iraq. As a result, the Taliban survived and eventually mounted a major comeback. Barack Obama decided to pour in troops and funds, but by that time, Afghan patience was nearing exhaustion.

So results keep falling miserably short of what's needed to produce lasting success. Lt. Col. Daniel L. Davis, who spent last year in a combat deployment touring Afghanistan, writes in the February issue of the Armed Forces Journal, "What I saw bore no resemblance to rosy official statements by U.S. military leaders about conditions on the ground."

Instead, he was told that the Taliban "controlled virtually every piece of land beyond eyeshot" of coalition military bases. "I observed Afghan security forces collude with the insurgency." He found American officers "who had nothing but contempt for the Afghan troops in their area."

The mutual ill will has become deadly. Two American officers were shot to death last week at the Afghan Interior Ministry, which is supposed to be one of the safest places in Kabul. But for U.S. military personnel, there are no longer any safe places.

Even official assessments of the war are discouraging. In a recent Senate Armed Services Committee hearing, Director of National Intelligence James Clapper predicted the Afghan government will make "incremental, fragile progress" this year, while noting the persistence of "corruption as well as poor leadership and management" in the police and army.

Lt. Gen. Ronald Burgess Jr., director of the Defense Intelligence Agency, told the committee that "the Afghan government will continue to struggle to fill the vacuum" left by coalition troops. The Afghan defense minister predicts "catastrophe" if the U.S. proceeds with plans to reduce the size of the Afghan force after 2014.

That leaves us in a catch-22: We can't bring peace and good governance to Afghanistan unless we stay a lot longer, but the longer we stay the more resentment and resistance we provoke. At this point, a U.S. officer who works on Afghanistan told McClatchy Newspapers, "Afghans hate us, and we don't trust them."

Americans who lived through Vietnam recall the image of helicopters evacuating our embassy personnel from Saigon as the enemy closed in. We may get to do the same thing in Kabul—but this time under fire from our friends.

Steve Chapman blogs daily at newsblogs.chicagotribune.com/steve_chapman