Superposition impacts Amper's Law by determining the net current enclosed by Amperian loops. When analyzing a system with two opposing currents, the loop outside the cylinder encloses zero current, resulting in a zero magnetic field. Conversely, the loop inside the cylinder encloses the current I, leading to a magnetic field equivalent to that of the wire. The distinction arises because the conductors are considered infinite, allowing for the application of this method. Understanding these principles is crucial for correctly applying Amper's Law in complex scenarios.