The distinction is relatively easily seen where the two roles are separated, say, the Queen and the Prime Minister in Britain or the President and the Prime Minister in India. In a parliamentary system the head of the State performs ceremonial duties. Normally the area of influence of ceremonial heads is very limited.
The real functionaries are the political persons who make the government and are headed by the Prime Minister. There is, thus, a clear difference between a executive and the executive; the authority of the former is nominal or titular whereas of the latter it is real or actual. There is wide difference between theory and practice here.
In terms of law the head of the State may be the source of authority, but his legal functions have become obsolete either as a result of binding conventions or as a result of Constitutional provisions.
When the same person plays both the roles of head of the State and head of the government, he combines unto himself the ceremonial as well as political responsibilities. [There is a single identifiable head of the executive, the President of the United States, ‘ who will also be the head of the State.
He is an executive as well as the executive. Under absolute monarchy and dictatorship the question of distinguishing the real from the nominal executive does not arise. Here all authority is concentrated in a single person or a group of persons.