Definition - What does Doctrine mean?
A doctrine is a principle, rule or policy that is a part of the law. Doctrines are often the subject of legal debates and/or trials.
One of the most famous doctrines was the Monroe Doctrine of 1823, which declared that an act of aggression by a European nation against any country in the Western Hemisphere would be considered an act of aggression against the United States.
Justipedia explains Doctrine
When a doctrine is approved, and becomes law, then the policies, theory or general concept behind it become legally enforceable. However, doctrines can be subject to change, and they can also be canceled. If a doctrine is canceled, and gotten rid of, then it is no longer a part of the law and no longer legally enforceable.
Doctrines can have massive legal implications. For example, the Monroe Doctrine helped to shape American foreign policy for decades after it went into effect.