President Hamid Karzai (Afghanistan)

Why? Karzai is a marked man, both as a U.S. ally and for trying to disarm militias and expand the rule of law.

Who? Taliban remnants working with al Qaeda are the most likely culprits, but rival Afghan leaders cannot be ruled out.

How? The possibilities are endless. A gunman fired four rounds into Karzai’s car in 2002. In 2004, Taliban members tried to shoot down his helicopter with rockets.

Then what? Tough call. A replacement could come from within his current government, but behind the scenes would be an uneasy junta made up of Afghanistan’s major players. Karzai will be a tough act to follow.

Worst case: Civil war. The assassination and jockeying for power could set the stage for renewed ethnic and tribal conflict. Reconstruction would cease.