Osama bin Laden's death a year ago, at the hands of a Navy SEAL team, revealed that America has been fighting two wars in Afghanistan. One is against al-Qaeda, and is clearly in America's national interest; the other war, to fix Afghanistan, is much more questionable. We must take lessons from the way we fight terrorism in Somalia, Yemen and elsewhere: Focus more on finishing the fight against al-Qaeda, and less on bringing good government to a failing state.

After 9/11, American special operations and intelligence personnel killed and captured al-Qaeda leaders, eliminated its bases of operation, restricted its financing, and disrupted its ability to launch international attacks. Relentless pressure has kept al-Qaeda's ability to conduct attacks low.

But in Afghanistan, it's hard to see whether American efforts are succeeding, and what we should do next. On 9/11 we were not attacked by a country. Yet because many Qaeda fighters were based and sheltered in Afghanistan in 2001, some Americans argued that to make victory permanent we had to not just oust the Taliban government, but also build a democracy, a modern economy and an effective national security apparatus for Afghanistan. It was like arguing that to put out a forest fire, we had to pave the forest.

Today, despite years of investment, the Taliban, associated fighters, criminal families and warlords still resist control from Kabul. President Hamid Karzai has been, at best, an unpredictable ally. Transparency International ranks Afghanistan as more corrupt than any country except Somalia and North Korea. Government security forces still cannot coordinate intelligence and operations across the country without our support.

Since bin Laden's death, many Americans have decided that our job in Afghanistan is done. They see a victory in the counterterrorism campaign, and are tired of the corruption, confusion and dysfunction of the nation-building campaign.

But it would be a mistake to abandon the country entirely, and fortunately, leaving altogether is not the only alternative. America has learned to fight al-Qaeda in other failed and failing states -- Yemen, Somalia and Pakistan -- without completely rebuilding them. It's time to bring those lessons learned back to where we started.

The weakness of the Karzai government need not pose any more of a threat to America than the ungovernability of large areas of Yemen and Somalia does. These areas must be watched closely by intelligence resources and cooperative tribal leaders, and any new threat must be cut down quickly. But that essential mission can be carried out by intelligence and Special Operations personnel who can smother remnants of al-Qaeda without having to rebuild every country where it sets up shop.

As the Obama administration negotiates with the Karzai government and with Pakistan, we may be tempted to make commitments that, in the name of nation-building, restrict our ability to fight terrorists. If we must involve the Afghan government in every night raid, our operations will slow and targets will escape. If Pakistani officials must know in advance of every drone attack, intelligence will leak.

Rather than asking how to support the Karzai government, we should be asking how, given the realities of Afghanistan, we can most effectively disrupt al-Qaeda operations and kill al-Qaeda leaders. An effective strategy should be built around eight principles:

* Maintain America's ability to strike al-Qaeda with surprise, speed and violence. Don't compromise it for the sake of a relationship with an unreliable ally;

* Focus on the mission, not the number of troops. Embedding Special Operations and intelligence personnel throughout the country will reduce our footprint without sacrificing our ability to hit al-Qaeda;

* Put in place a long-term plan for maintaining effective signals and human intelligence. Intelligence is easily overlooked in talk about "boots on the ground," but is our first line of defense;

* Make clear that our support for Afghanistan's army and national police force depends on their ability to counter international terrorist attacks. Our continued investment must be dependent on their performance;

* If the Karzai government can't get the job done, work with people who can. Local allies like tribal leaders can be partners. Our time should be spent working directly with them, rather than trying to get them to partner with Kabul;

* Expand our options by strengthening relationships with nearby governments, while ensuring that our plans for naval deployments maintain effective cruise missile and aircraft carrier strike capabilities;

* Be true to our friends. See that Afghans who have taken risks serving with American forces -- translators, for example -- are cared for, along with their families;

* Remember what constitutes success. Success means eliminating al-Qaeda's ability to launch terrorist attacks against the United States and our allies.

Achieving that goal demands focus. Defeating a terrorist organisation is like fighting a forest fire; there's never a clear moment of victory, and even after you've won, you have to watch carefully. The successes of the past decade have required discipline, focus and sacrifice from America's service members and their families. Now, to complete that mission, we must ask no less of our policy makers.

The writer, a former Navy SEAL, is the author of The Heart and The Fist: The Education of a Humanitarian, the Making of a Navy SEAL.

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