Much of the rationale for the U.S. involvement in Afghanistan has to do with making sure that it doesn’t become a haven for militant groups once again. As President Barack Obama weighs U.S. and NATO commander General Stanley McChrystal’s recommendation for 40,000 more troops at a time of fading public support for the war in Afghanistan, some people are questioning the basic premise that America must remain militarily committed there so that al Qaeda doesn’t creep back under the protection of the Taliban.

Richard N.Haass, the president of the Council for Foreign Relations, kicked off the debate this month, arguing that al Qaeda didn’t really “require Afghan real estate to constitute a regional or global threat”. Terrorists head to areas of least resistance, and if it is not Afghanistan, they will choose other unstable countries such as Somalia or Yemen, if it hasn’t happened already, he argues. And the United States cannot conceivably secure all the terrorist havens in the world.

Some experts argue that physical space isn’t really the key to militant groups survival anymore in the age of the Internet. Paul R Pillar, a former CIA counterterrorism official, said in a piece for the Washington Post that safe havens were usually used by militants to hold basic training for recruits. The operations most important to future terrorist attacks do not require such a home, and he cites the Sept 11, 2001 attacks as an example. “The preparations most important to the attacks took place not in camps in Afghanistan but, rather, in apartments in Germany, hotel rooms in Spain and flight schools in the United States,” he says.AFGHANISTAN/

In the past couple of decades, international terrorist groups have thrived by exploiting globalization and information technology, which has lessened their dependence on physical havens. it’s not that a sanctuary such as Afghanistan will not help al Qaeda; or other militant groups; the issue is whether denying them the space will prevent an attack, and that, Pillar says, is no longer guaranteed.

But Jim Arkedis, director of the National Security Project at the Progressive Policy Institute and a former Pentagon counter-terrorism official, argues that the value of physical space cannot be underestimated and that a “homeless al Qaeda is the best guarantee against large-scale attacks.”

It is certainly true that militants can accomplish much online, he concedes in a piece for Foreign Policy. Individuals can maintain contact with groups via chat rooms, money can be transferred over the Web (if done with extreme caution), and plotters can download items like instruction manuals for bomb-making, photographs of potential targets, and even blueprints for particular buildings.

But all the e-mail accounts, chat rooms, and social media available will never account for the human touch. “There is simply no substitute for the trust and confidence built by physically meeting, jointly conceiving, and then training together for a large-scale, complex operation on the other side of the world,” Arkedis, who spent the last five years studying terrorist plots, says.

Even in the Sept 11 attack there were preparations that took place along the Afghanistan-Pakistan border, where mastermind Khalid Sheikh Mohammed put future operatives through a series of training courses. These included physical fitness, firearms, close combat, Western culture and English language.

You can learn lots of things online, but it is still preferable to have a dedicated professor physically present to supervise students and monitor progress, he says.

[Reuters photos of a U.S. Marine in Helmand and a woman walking past a protest in Kabul]