Formation of the state of Bhutan (?Brug gzhung) in the 17th century and its Tibetan antecedents

The relationship between religion and the state has remained a perennial issue of the Tibetan cultural presence since the 7th century. The question is how the definition and actuality of that relationship evolved over fourteen centuries, both
theoretically and in the practical implementation of governing structures. On what moral or normative religious grounds have the various Tibetan governments justified their existence? Conversely, what political assertions or compromises have religious institutions made to achieve a privileged, or at least defined and workable, relationship with the entities of civil governance?