[This Op-Ed was published in The Hill on April 24, 2002. It was retrieves from archives and does not appear to be available on http://www.thehill.com] As President Bush told the American people immediately after Sept. 11, the fight against international terrorism will require a prolonged effort. The initial war to take down al Qaeda began in Afghanistan, and while we have enjoyed some success in that fight, we have only just begun. Now comes the hard part, and the stakes are very high. Those who believe our military mission has been accomplished and that the United States can pull out of Afghanistan relatively soon ignore the fundamental reason we went there in the first place, and the conditions that exist today. If the United States remains committed to preventing Afghanistan from once again becoming a lawless state that serves as a safe haven for terrorists like bin Laden to operate with impunity, our work is not complete. Notwithstanding what our military has accomplished, security and stability in Afghanistan are far from assured. No one seems to have a clue where bin Laden is today, al Qaeda is still a force, and Afghanistan is in grave danger of backsliding into chaos. Earlier this month, hardcore militants were captured in Kabul with plans to assassinate Afghanistan's interim leader, Hamid Karzai. They wanted to derail plans for the Loya Jirga - the Grand Council - and kill as many U.S. and western troops as they could. The author of the plot, Gulbuddin Hekmatyar, ordered much of the destruction of Kabul during the 1990s and is one of the most vicious warlords in recent Afghan history. Before his return to Afghanistan, he had been living in Iran, and he maintains very close ties to the government there. In the western city of Herat, General Ismail Khan rules as a semi-independent baron and entertains emissaries from Iran who may be anxious to extend their sphere of influence. In short, Karzai's interim government exerts very little control over most of the country, and he remains anxious to have a strong international security force in Afghanistan to help establish security. With security, all else will follow. Without it, nothing will succeed. Without a strong multilateral force helping Karzai's government extend its authority throughout the country, Afghanistan's enormous reconstruction and development needs will not be met. Whether it is economic reconstruction, building political institutions, clearing minefields, or creating the educational and medical infrastructure necessary for long-term self-sufficiency, none of it is possible without the prerequisite of security. But make no mistake, succeeding in Afghanistan is critical to U.S. national security, and we must not allow our resolve to wane even though progress often is slow. We haven't gotten bin Laden. Al Qaeda is still there, seeping across the border to and from Pakistan, apparently at will. The Taliban has melted into the hills, but has not been eliminated. We've never found Mullah Omar. If Afghanistan fails, we will pay a heavy price. If we don't stay the course, the "swamp" everyone talked about will fill up once again. If we don't stay the course, other nations in the region, especially Pakistan, will be in great jeopardy. To help stabilize the situation, there are four next steps in Afghanistan we must take. First, the International Security Assistance Force of 5,000 troops presently confined to Kabul should be extended to Mazar, Kandahar, Jalalabad and perhaps to Herat and Gardez. Some estimates show that such an expansion would require an increase to 25,000 troops, but we should commit however many troops military experts determine are necessary to do the job right. Second, the mandate of the International Security Assistance Force should be extended for two years. This would provide sufficient time for the creation of an indigenous Afghan army and police force, and ensure a smooth transition to the new Afghan government. Third, the international security force must be given robust rules of engagement, and all the equipment, airlift support and intelligence necessary to accomplish the mission. These troops are not, and must not be, blue-helmeted peacekeepers. They are, and must be, international peacemakers. We need rough, tough, combat-ready forces with the ability to impose order. And fourth, the United States must be fully engaged as the mission's guarantor of last resort. That means we must commit ourselves to the success of the mission and it means we should not rule out the use of American troops if necessary. I would prefer that we accomplish our mission without deploying a single U.S. soldier, and I would prefer that other nations accomplish the task without our troops on the ground. But recent experience, in the Balkans and elsewhere, suggests it's highly unlikely this will be possible. The bottom line is that we have a mission to accomplish, and if the deployment of American troops is deemed necessary, we must step up to the plate to assure success of the mission. Afghans are wondering if the United States has the will to get the job done. And other allies and adversaries, in the region and elsewhere, are watching closely to see if we will stay the course. Leadership matters, and American leadership matters most. As the world's only superpower, and as a nation determined to win the fight against international terrorism, we have no choice but to act with uncompromising resolve to further our national interests. Sen. Biden, a Democrat from Delaware, is chairman of the Foreign Relations Committee.