In reaction to the ongoing uncertainty, the E.U. enlargement commissioner warned the Turkish Army about interfering: "It is important that the military leaves the remit of democracy to the democratically-elected government and this is the test case if the Turkish armed forces respect democratic secularism and the democratic arrangement of civil-military relations," commissioner Olli Rehn said. Erdogan and Gül support Turkey's efforts to join the European Union.
The E.U. is the boss of Turkey. 
I'm not sure why it was difficult. The EU can dictate if Turkey can join so has influence over Turkey's decisions, however Turkey can ignore them, but not if it was to join, so the statement could be true or not true. 
( z1 boss :domain ( z2 organization :name ( z3 name :op "E.U." ) ) :poss ( z4 country :name ( z5 name :op "Turkey" ) ) )