Final answer:
The US Supreme Court emphasized different principles during different periods of US history, including the national supremacy principle, dual federalism, and considering the Constitution in light of changing social needs.
Step-by-step explanation:
The US Supreme Court emphasized different principles during different periods of US history. From 1819 to the 1860s, the Court focused on settling power struggles between the states and the national government, establishing the national supremacy principle. In the late 1870s, the Court followed the concept of dual federalism, with the states and national government exercising exclusive authority in distinct spheres. By the early 20th century, the Court began considering the Constitution in light of the country's changing social needs.