Basically, to establish Public Administration as a separate discipline, Woodrow Wilson and many other scholars in later 19th century started giving argument that the background and the role of Public Ad. is quite distinct from Political Science. They advanced the following arguments :-
1. Political Science deal with policy formulation and Public Administration with policy implementation.
2. Political System involving policy formulation is based on ideology, philosophy and aspirations of the people. But Public administration concentrates on facts, value-free, neutrality, rationality and objectivity. Therefore, public opinion is representation in political system but not in public administration.
3. Political System deals with decision making, while public administration with advisory role. The decision making by the political system is to be based on the neutral, rational and impartial advice given by he Public Administration.
4. Since political system has to represent the public opinion, politicians are elected. However, since administrative system necessitates competence, knowledge and abilities, administrators are selected.
5. Political systems is temporary, while Public Administration provides stability and continuity to the system. That's why we differential between political executive and permanent executive. Thus though ideology and policy of political groups may change, but the system remains stable continuous.
6. Emerging from the above Point, it states that Public Administration is confined only to executive wing of the government and no the legislative and judicial organs of the government (Horizontal Differentiation).
7. Amateurs vs. Professional : No formal qualifications for members of political system are required. This is not only in India but elsewhere also where administrators are professional people.
However, all these above arguments relating to the difference between Political Science and public administration are not relevant in the present times. This is explained as follows : Policy formulation is based not only on political dimension but also on administrative dimension. Policy formulation can be done without understanding the procedures of policy implementation. Therefore, both are inter-woven. Even this is said that the real policy is actually formed by the administrators to which politicians merely sign.
Similarly, to say that Public Administration deals only with the executive branch of government is wrong. It covers other two organs - legislature and judiciary as well. For instance, the concept of delegated legislation involves the legislative functions by the administrators, and thus indicates the rule making powers of the administration. Conversely, there is a lot of administration involved in legislation (law-making). Similar, for judicial powers, a lot of administrative authorities have been vested with judicial powers of adjudication. e.g. Magistrate, Income Tax officials, traffic police etc. all involved judicial functions by administrators. conversely as well, judiciary too requires and administration.