What's the difference between Libya and Yemen or Bahrain?
All three states have been using violence to crush pro-democracy protests.
But only against Libya are the US and its Western allies planning a military response.
Yemen and Bahrain's crackdowns have so far been met only with words, not action.
On one level the answer is obvious.
Bahrain and Yemen are US allies - especially Bahrain with its large US naval base. Libya is not.
The US response to Bahrain is further complicated by neighbouring Saudi Arabia, Washington's number one Arab ally. More...