Lets go back to 1951-52 and the negotiations for Greece and Turkey to join NATO. At the time there was apparently significant British pressure for Turkey to join instead only what was to become the future Baghdad pact, CENTO instead of becoming a NATO member as well. In the end British disagreement was overcome and Turkey joined NATO on schedule. Interestingly enough given what was going to follow, Greece at the time closely allied to Turkey would steadfastly support Turkish entry into NATO simultaneously with her own entry during the whole episode.
But say instead that the Brits have their way. Come 1952 Greece becomes the 13th NATO member, while Turkey goes on to become a founding member of CENTO a couple years later.
Initially you might not see much of a difference. Turkey will still be receiving MAP aid from the US, although Greece might get a little higher funding and Turkey a little less, the Turkish political elite will be somewhat pissed at getting snubbed at joining the Europe only club but life goes otherwise on, while Greeks and Turks launch a renewed campaign for Turkey to join NATO.
Things though get fun rapidly from there. The Cyprus emergency begins on schedule in April 1955, the September pogroms against the Greek poulation in Turkey follow bringing down the Greco-Turkish alliance of the previous years and Greek-Turkish relations keep deteriorating from there. Only this time this is happening between a NATO member and a pro-Western nation that is nevertheless outside NATO
The first two points this becomes significant is probably during the Zurich agreements ending the Cypriot emergency and the Turkish coup in 1960. In the first case perhaps we might see something like the Acheson plan or the earlier Harding proposals instead of the Cypriot state of OTL with Turkey being out of NATO. In the second there was a significant "Nasserist" faction of extremist officers of which Alparslan Turkes future leader of the Grey Wolves was the front. OTL he'd lose out to the moderates under army chief of staff Cemal Gürsel in the post-coup struggle for control and Turkey would go on to become the "managed democracy" of OTL with further army coups in 1971 and 1980, the so called "post-modern coup" of 1997 and last the 2016 coup. But in a relatively more radicalized Turkey, with less NATO influence within its army does Turkes still lose out to the moderates or we see Turkes trying to imitate Nasser at the head of 1960s Turkey?
Thoughts?