How to accomplish these goals? Clear, hold, and build.
Additional troops will be successful only if they are employed correctly. Relearning the classic "clear, hold, and build" counterinsurgency model took several years in Iraq, but to date there are insufficient international or Afghan forces to hold areas that American troops have cleared of insurgents. As a result, the troops have had to clear the same areas repeatedly—paying a price for each operation in both American lives and in Afghan public support, which suffers from Taliban reprisals whenever we "clear and leave."
The alternative requires not just more troops but a different strategy. After an area is cleared of insurgents, it must be held by Afghan troops supported by American advisers and combat multipliers, including artillery and air support. Inside this bubble of security, the Afghan government can re-establish control and build a better and more prosperous community with the help of a surge of American civilian advisers. Since 30,000 more troops won't be enough to secure the whole country, we'll have to select the most important population centers, such as Kabul and Kandahar, to secure first. These "oil spots" of security will then spread over time—a long time. The single most important reason not to think of the new strategy as a surge for Afghanistan is that the term surge is associated with the relatively short-term ramp-up of forces in Iraq. In Afghanistan, the additional forces will be required for the long haul.
Back in September, Adm. Mike Mullen stressed that the need for more security was urgent: "Frankly, we're running out of time," he said. The situation has worsened since then, and the clock is still ticking. While a surge of troops is urgently needed, they must be a component of a new strategy; this ends, ways, and means formulation is one way to think about where we want Afghanistan to go and what it will take to get there.