Essential characteristics of a federal constitution are as follows.
1) Distribution of powers -
The distribution of powers is an essential feature of federalism . Federalism means the distribution of powers of the state among the number of coordinate bodies each originatinf in and controlled by the constitution.
2) Supremacy of Constitution -
A federal state derives its existence from the constitution. Hence, every power, executive, legislative or judicial whether it belongs to the nation or the individual state is subordinate to and controlled by the constitution. The constitution in a federal state constitute the supreme law of the land. According to Prof. Wheare that those two institutions - the supreme constitution and the. written constitution are then, essential institutions to a federal government. The supermachy of constitution is essential if a government is to be federal.
3) A written constitution -
A federal constitution must almost necessarily to be a written constitution. The foundations of a federal state are complicated contracts. It will be practically impossible to maintain the supremacy of the constitution unless the, terms of the constitution have been r reduced into writing.
4) Rigidity -
A natural of a written constitution is its rigidity . A constitution which is the supreme law of land must also be rigid. In a rigid constitution the procedure of amendment is very complicated and difficult. This doesn't mean that the constitution should not be legally unalterable. It simply means that the power of amending of the constitution should not be remain exclusively with either the central or state governments. A constitution of a country is considered to be the permanent document. It is the supreme law of land. The Supermacy of the constitution can only be maintained if the method of amendment is rigid.
5) Authority of courts -
In a federal state the legal supremacy of the constitution is essential for the existence of federal system. The very nature of the federal state involves a division between the central and the state governments under the framework of the constitution. It is therefore, essential to maintain this division of powers between the two levels of governments. This must be done by some independent and impartial authority above and beyond the ordinary bodies whether federal or state legislature or State legislature existing under the constitution. The judiciary has, in a federal polity , , the final power to interpret the constitution and guard the entrenched provisions of the constitution