This chapter analyzes Turkey’s rapprochement with Russia, particularly in security and defense. It analyzes two case studies: Turkey’s declared intent of becoming a member of the Shanghai Cooperation Organization (SCO) and the agreement signed with Russia to buy a missile defense system. It argues that Turkey’s intention to become an SCO member may be labeled as a compellent threat for alternative alliances against the West. Hence, it represents boundary challenging. Furthermore, by signing an agreement to purchase an S-400 missile defense system, Turkey signals to the West that the NATO defense shield system is not the only alternative and engages in collaborative balancing with Russia on defense. Representing boundary breaking against the West, as an S-400 missile defense system would not only be incompatible with the defense network of NATO but also risk intelligence infiltration into NATO’s networks. Turkey signals its resolve to engage in cooperative balancing with Russia, as it does not give in to the threats that its potential F-35 deal with the USA would be jeopardized, uses blackmail power, and makes compellent threats, which indicate a switch to boundary breaking.