Federal System
India, a union of states, is a Sovereign, Secular, Democratic Republic with a Parliamentary system of Government. The Indian Polity is governed in terms of the Constitution, which was adopted by the Constituent Assembly on 26 November 1949 and came into force on 26 November 1950.
The President is the constitutional head of Executive of the Union. Real executive power vests in a Council of Ministers with the Prime Minister as head. The Council of Ministers is collectively responsible to the Lok Sabha, the House of the People.
In the states, the Governor, as the representative of the President, is the head of Executive, but real executive power rests with the Chief Minister who heads the Council of Ministers. The Council of Ministers of a state is collectively responsible to the elected legislative assembly of the state.
The Constitution governs the sharing of legislative power between Parliament and the State Legislatures, and provides for the vesting of residual powers in Parliament. The power to amend the Constitution also vests in Parliament.
The Union Executive consists of the President, the Vice President and Council of Ministers with the Prime Minister at the head to aid and advise the President.
President
The President is elected by members of an electoral college consisting of elected members of both Houses of Parliament and Legislative Assemblies of the states, with suitable weightage given to each vote. His term of office is five years.
Among other powers, the President can proclaim an emergency in the country if he is satisfied that the security of the country or of any part of its territory is threatened whether by war or external agression or armed rebellion. When there is a failure of the constitutional machinery in a state, he can assume to himself all or any of the functions of the government of that state.
Vice-President
The Vice-President is elected in the same way as the