1. Division of Powers:
In a federal government, the powers of administration are divided between the centre and the units. The powers may be distributed in one of the two ways. Either the Constitution states what powers the federal authority shall have and leaves the remainder to the federating units, or it states what powers the federating units shall possess and leaves the remainder to the federal authority.
The remainder is generally known as residuary powers. The first method was employed in America and the second in Canada. The federal government in U.S.A., for example, is weak in relation to the states and reverse is the case with Canada.
2. Written Constitution:
A federation must have a written constitution. A federation is a political partnership of various states and consequently there must be a written constitution.
3. Rigid Constitution:
The constitution of a federation should be better rigid so that it could be regarded as a sacred agreement, the spirit of which should not be easily violated. A flexible constitution allows scope to the central government to curtail the autonomy of the federating states.
4. Special Judiciary:
In a federation there are possibilities of constitutional disputes arising between the federal centre and the units or between one unit and another or between the citizens and the government. All these disputes are to be adjudicated in the light of the constitution.
For this purpose a special judiciary with wide powers must be established. It should act as the custodian and guardian of the constitution. It should be vested with powers of declaring any law, national or local, ultra vires if it is at variance with the articles of the constitution.
5. Supremacy of the Constitution:
The constitution is the supreme law in a federation. Neither the central government nor the government of the units can go against its spirit.
6. Double Citizenship:
Citizens in a federal state have dual interests and they should be given rights of double citizenship—citizenship of the state wherein they are domiciled and citizenship of federal state as a whole.
7. Bill of Rights:
Citizens in a federation enjoy certain rights given to them by the constitution. The constitution of India, Russia, and the U.S.A. have given rights to the citizens. It is a well established custom now.