As every American learned from the attacks of Sept. 11, 2001, ungoverned or poorly governed nations can become safe havens for terrorists to plan and launch attacks against our homeland and interests abroad. That was the case in Afghanistan, where the Taliban harbored Osama bin Laden and many of his al-Qaida terrorist operatives.

Nearly 10 years later, the death of bin Laden three weeks ago has reinvigorated the debate about our ongoing operations in Afghanistan. It is fair to ask why we stay engaged there given the substantial human and financial costs.

The death of bin Laden does not remove the threat of terrorism. To be sure, his death was a hard-fought victory and an important milestone in the global fight against terrorism. Every day that bin Laden lived was in itself an inspiration to al-Qaida and other terrorists, so having him gone removes that inspiration. So far, nobody else has arisen with the same aura or charisma that allowed him to act as a unique and unifying force.

Unfortunately, bin Laden’s death does not mean we can relax; quite the opposite, actually. Every day, terrorists are plotting and planning against this country and our citizens. One needs just to look at the pace of planned or attempted terrorist attacks inside the United States recently — including the 2009 Christmas Day bomber, the thwarted Times Square incident, the Fort Hood shooting and the cargo plane bomb plot that originated in Yemen.

In the short term, our troops and the country may be in increased danger as other terrorists lash out to prove they are still viable, like we saw with the twin Taliban suicide bombers in Pakistan claiming to avenge bin Laden’s death. We need to make sure Afghanistan remains off-limits to those who are still actively seeking to do us harm.

Ten years after 9/11, Afghanistan remains important to the safety and security of America and our allies. It is important to continue to remind ourselves why we remain there today.

First, Afghanistan is a kind of spiritual center for the Taliban and al-Qaida. Terrorists want to be there. The country is remote, primitive and isolated — and it has difficult terrain. It is an ideal place to recruit, train and house terrorists, as well as to plan terror attacks. Having just returned from a trip there, I can confirm our service members have made great strides.

Yet, while we have made tremendous progress, our work is not done. The Taliban has launched a spring offensive. Afghan security forces need to continue training and their ranks must continue to grow. And, in just the 90 days from Feb. 4 to May 6, the NATO coalition in Afghanistan — known formally as the International Security Assistance Force — conducted more than 1,400 operations, capturing or killing nearly 510 insurgent leaders and more than 2,700 lower-level insurgents. In March, Afghan and coalition forces seized more than 105,000 pounds of narcotics — a more than 700 percent increase from the same month a year before. Such raids put strong pressure on the Taliban and other insurgent groups who use income from these drugs to finance their operations.

Another equally important reason for our efforts in Afghanistan is its strategic location. Afghanistan and Pakistan are inextricably linked — culturally, geographically and religiously. What happens in one country affects the other.

As we have seen during the past year, the United States’ relationship with Afghanistan’s next door neighbor, Pakistan, is increasingly tense and troubling. Pakistan has generally been cooperative in the fight against core al-Qaida, although we must have greater cooperation to track down and remove al-Qaida operatives hiding there. Pakistan’s commitment to combating the Taliban and other extremists, however, is not as strong as it should be.

There seems to be a struggle within that country to identify who the extremists are and what the threat is. That is problematic given that Pakistan is nuclear-armed. And so it is imperative that the United States makes sure Pakistan and Afghanistan remain as stable as possible.

Perhaps Defense Secretary Robert Gates summed it up best when, speaking to NATO allies in March, he said, “Frankly, there is too much talk about leaving and not enough talk about getting the job done right.”

He added: “Too much discussion of exit and not enough discussion about continuing the fight. Too much concern about when and how many troops might redeploy and not enough about what needs to be done before they leave.”

The instinct to want to wrap things up in a nice, neat package is a natural human response to a long and difficult conflict. The global war against terrorism, however, is no ordinary conflict. I want our men and women to be able to come home as soon as they possible. America has never benefited from quitting before a job is done. We must see this mission through. Because, even though we have succeeded in removing al-Qaida’s leader, success in Abbottabad on one day does not ensure victory in Afghanistan or against terrorism tomorrow.

Rep. Mac Thornberry (R-Texas) is chairman of the Armed Services Subcommittee on Emerging Threats and Capabilities and the third-ranking majority member of the Intelligence Committee.