Every country has its constitution. The Constitution is not a Holly Book but it is taken from the experiences of different aspects of society. every citizen of the Country is bound to obey the Constitution.
Here are some Important sources of U.S Constitutional Law:
The Legislation is the most important Source of American Constitutional Law. The Constitution as originally drafted was merely a Skelton and the details were left to be filled in by the Congress and the State Legislatures.
The Constitution authorises the Congress to make all laws which are necessary to carry out the powers assigned to it. By the use of this power, The Congress has set up a huge defence establishment, created many administrative boards and bureau, " annexed a far-flung empire, entered into the business of education, banking, insurance, construction, transporting generating electric power and found authority to regulate the complicated nation".
Traditions have made the constitution flexible and have added to the powers of the National Government.
The President's cabinet developed from the words in the second Article that permits the chief Executive to " require the opinion, in writing of the principal officer in each of the executive departments, upon any subject relating to the duties of their respective offices...".
Amendments are also a source of American Constitution.There have been 26 amendments so far(1972). the first 10 amendments took place in 1791. The other amendments were made time to time.The amendment process is difficult.
Interpretation By Courts:
Interpretations are also important source of American Constitution. Judicial Review is the authority of judges to interpret the Constitution.
The study of U.S.A Constitution is a study of judicial decisions and opinions of Jurists.
Decisions Of The Executive:
The president has all the powers. Though the Constitution provides indirect election of the president but in practice his election has become direct.
Presidents like Roosevelt, Lincoln, Jackson And Washington have influenced the Constitution in many ways.
The American Constitution is also consists of Conventions.
The first president of America, George Washington established a convention that a President should not continue for more than two terms.
There are many other sources like Customs, local laws, etc. But due to unnecessary length, subject is ended here.