well let us not focus just on them, European colonialism as a whole did not end until the 1960s and by then the damage was done. The Arabian peninsula and surrounding areas were pretty much divided up with borders created to respect European influence and not consider much of the existing structure, hence the strife that goes on to this day. The US and USSR meddling while extensive came at a much later date and involved states created prior to their involvement with very little changes to borders.
Remember, France wasn't thrown out of Vietnam until the 1954 and had to be thrown out of Algeria a decade later.
Remember, France wasn't thrown out of Vietnam until the 1954 and had to be thrown out of Algeria a decade later.
https://en.wikipedia.org/wiki/History_of_colonialism