Final answer:
The basis of all law in the United States is the United States Constitution, making Constitutional law the correct answer. The Constitution is the supreme law of the land and establishes the framework for government and law, which is then interpreted through the common law system.
Step-by-step explanation:
The United States Constitution is the fundamental and highest basis of all law in the United States. This means that the correct answer to the student's question is Constitutional law. The Constitution creates the branches of government, defines their powers and limitations, and establishes basic rights and obligations. It is followed in the legal hierarchy by federal treaties, federal laws, state constitutions, state laws, and finally local ordinances. Notably, while common law is crucial for the development of the American legal system and judicial decisions, it is not the basis of all law in the country. Instead, it plays a vital role in interpreting statutory and constitutional provisions in the absence of statute.
Under the system of judicial review, the courts have the power to evaluate laws and determine whether they are in compliance with the Constitution. It is important to understand that no law, be it federal or state, supersedes the Constitution, which is explicitly stated as the 'supreme law of the land' in the Constitution itself. Thus, the Constitution is the foundation upon which all other laws and legal frameworks in the United States are built.