It lets America drive three-quarters of its war supplies from Karachi, and goes along with immensely unpopular drone strikes against extremists in its own tribal areas.

ECONOMIST: Pakistan and India

Washington also wants an aggressive push by Pakistani authorities to take action against al Qaeda-linked groups in the largely ungoverned tribal areas along its border with Afghanistan.

CNN: By the CNN Wire Staff

Libya's population is a quarter the size of Iraq's, and the country should be easier to control: almost all its people, a more homogeneous lot albeit with sharp tribal loyalties, live along the Mediterranean coastal strip.

ECONOMIST: The challenge of Libya

Goaded (perhaps unwisely) by America, it has sent 80, 000 troops into its tribal border area, thereby starting a war with tribesmen in which 800 soldiers have died.

ECONOMIST: Pakistan: School for terror | The

Pakistan's army made it known that in the event of conflict with India, it would move its troops from the tribal areas.

ECONOMIST: Deny, co-operate and cross your fingers

With its rough terrain, weak central state and gun-slinging tribal culture, Yemen may prove a fairly secure redoubt for al-Qaeda.

ECONOMIST: Yemen and al-Qaeda