Problem 1: Define the principle of non-refoulement.
Problem 2: What is its standing in International Law?
Problem 3: What purpose does it serve in refugee law and protection?
Problem 4: Does it apply to asylum-seekers as well as refugees?
Problem 5: Discuss its evolution in light of all relevant international instruments.
Problem 6: Discuss its standing in, and application by, the United States.
Note: Please be direct and precise about answering the question. Give some examples (case references). Pay attention to the question carefully in-order to answer / research correctly.