My friend Shaun Mullen mentioned this in his post below but I think some further talk about the Sykes-Picot  Line might be useful.  The Ottoman Empire collapsed at the end of WWI.  That left a large chunk of Mesopotamia open for grabs and both the British and the French who were still anxious to expand their empires were ready to grab.   As Shaun noted:

 When the British diplomat Sir Mark Sykes sat down with François George-Picot, his French counterpart, on May 16, 1916 in London for the last in a six-month series of tea-and-negotiation meetings, it was the pilot episode of a sort of a real-life Game of Thrones.

This was in 1916 and may well have been the start of the 20th century turmoil in the middle east.  Keep in mind their interest was not to create  a stable  area but to divide up the spoils of war to increase their empires.  Since they were just as ignorant of the people and cultures of the area as the Bush/Cheney they created a monster .  They never took into consideration the tribal, sectarian,  secular or ethnic situation that existed in the area.  Instead they created three artificial countries,Lebanon, Syria and Iraq, totally divorced  from reality.  Note, we can argue  about who is responsible for the current chaos in Iraq, and there are many who are responsible , but the seeds of the chaos were planted by British and French imperialism in 1916.

Note:

Map from Wikipedia that has a lot more information.