"In Muslim tradition, the world is divided into two houses, the house of Islam and the house of war." (B.Lewis)
Not a great deal to comment on here. I would like to point out how this ‘tradition’ demonstrates Islamic attitudes and foreign policy.
At least part of the reason why Islam is so hostile is because so many of the ‘laws’ that dictate foreign policy allow for this attitude as they specify when truces are to be made and when war can commence. In general terms, wars are to be fought when Islam can win. And when Islam is at a disadvantage or losing, truces can and should be implemented. Note how truces are specified, and not peace. Peace can only be accomplished when Islam is dominant and the area in question is within the ‘house of peace’ or under Islamic control. In other words, continuous warfare until no other places exist outside of the ‘house of ‘peace’. If this does not supply a full amount of excuses to start wars, I do not know what else will.