Problem with analysing the 'Obama Doctrine'

POLITICAL scientists have embraced the notion that every modern American president had a foreign policy "doctrine". Some of the most famous include the Truman Doctrine, the Nixon Doctrine, the Reagan Doctrine and, more recently, the Bush Doctrine.

We seem to take it for granted that every US president has had a unique and coherent foreign policy strategy that reflected his perception of American national interests and the country's place in the world, and that, in turn, was a product of his vision of history and personal temperament.

A foreign policy doctrine aka Grand Strategy "assumes certain national goals, ends, or interests", identifies "existing challenges or threats to those interests", and "selects and recommends the particular policy instruments or means by which challenges are met and national goals pursued", according to George Mason University professor Colin Dueck. Which bring us to the question: Applying the above definition to President Barack Obama's foreign policy during his two terms in office, is there an Obama Doctrine?