Foreign policy analysis as an academic discipline examines how states, the main actors of international relations, respond to external developments and engage with other actors (Neack, 2008).

Kenneth Walzt, one of the founding fathers of modern International Relations disciple, argues that there exist three images in international relations, which are first, second and third images (Waltz, 1954). First image is about the leaders and statesmen who are in charge of their countries. Second image is about the state-society level factors, whereas the third image is very much about the impact of international systemic factors on foreign policy

Classical realism puts the main emphasize on individual factors and prioritizes the role of leaders and statesmen in the formulation and conduct of foreign policy decisions.

Liberal pluralist perspective values the role of societal and intra-state level factors in foreign policy analysis. States are not unitary actors and their internal characteristics would decisively shape their foreign policy preferences and actions (Jackson and Sorenson, 2003, 105-137).

Structural realism does on the other hand single out distribution of material power capabilities among states and the anarchical structure of international system as the most important explanatory factor in this regard and turns a blind eye to the potential impact of individual and internal factors on foreign policy (Waltz, 1979).

Recent years have also witnessed the rise of another alternative theoretical perspective on foreign policy, namely neoclassical realism. This school of thought tries to combine the insights of structural realism with those of classical realism and liberalism. It offers a more holistic account of foreign policy (Lobell, Ripsman and Taliaferro, 2009).

Both the organizational behavior and the bureaucratic politics models suggest that the state should not be considered as a unitary actor with one single predominant leader holding monopoly over national foreign policy issues. This view is in line with more liberal then realist international relations theory.

Rational Actor model assumes that leaders act rationally in foreign policy. States are considered to be unitary actors behaving rationally in their relations with other international actors (Neack, 2008, 31-39).

As regards the internal factors that play a role in foreign policy, the nature of political regimes, national role conceptualization of ruling elites, strategic culture, political ideologies, religion, interest groups, civil society organizations, public opinion, and etc. stand out the most (Breuning, 2007, 115-140).

The scholars who focus on internal factors in explaining foreign policies of states assume that states are not unitary actors and what goes within states matter a lot. States cannot be considered as black boxes interacting with each other as billiard balls.

The American foreign policy in Middle East, particularly the US-led occupation of Iraq in 2003 and the regime transformation approach that the George W. Bush administration adopted in the wake of the 9/11 attacks, demonstrates that liberal democratic countries also employ military/coercive tools in their foreign policy.

National role conceptualizations are also important because how ruling elites define the mission and vision of their countries affects their engagement with others.

Their impact is mainly bottom-up because their aspiration is to influence the key decision makers at the state level by helping arouse organized public pressure at the societal level. Whereas some of them are active in the field of economics, some other are quite influential in the fields of environment, religion, human rights, and etc. Their financial capabilities, organizational strength and ability to have access to decision makers would eventually affect the degree of their success. The ability of such societal groups to become influential in foreign policy seems to be closely interrelated with the nature of the political regime. 

The third set of factors that might help analysts make sense of foreign policy of states is external factors. Focusing on external factors is mostly emphasized by realist and structural realist scholars in International Relations.

In general, the degree of states’ maneuvering capability would be the highest in multipolar systems because states would be able to align with multiple powers, play one power off against another, and change alliance relations easily.

Bipolar systems would more heavily constrain states, because there would only exist two major poles/powers. Choices would be more limited in their external relations. The
ability of middle and small sized powers to resist the foreign policy demands of the major power with which they align would be extremely limited.

The Cold War period between 1949 and 1989 is the best example of the bipolar international environment. In such systems, the possibility of middle and small-sized countries to pursue multidimensional and multidirectional foreign policies in defiance of their alliance commitments would be extremely low.

Geographical location is another factor emphasized by the ones who focus on external factors in explaining foreign policy of states. The first point to underline in
this regard is the number of neighbors states have. Should states neighbor with many states, they would be more predisposed to prioritize territorial security concerns. The degree of internal factors determining foreign policy choices and behaviors of states with multiple neighbors would be extremely low. Foreign policy of such states can therefore be defined as their responses to external stimuli. 

Third, the importance of geographical location also manifests itself in the sense of states leveraging their particular geographical features in their foreign relations. Some states, such as Turkey, lie at the intersection of different regions and continental landmasses and this gives them immense bargaining power with third parties. In the context of transporting gas and oil resources of Central Asian, Middle Eastern and Caucasian regions to western European markets, Turkey can act as a transit country

Russians tend to view Turkey as a key country in their historical efforts to reach out to the hot waters in the Mediterranean. That Turkey possesses the Bosporus and Dardanelles straits caused great tension in Turkey’s relations with Russia in the past?