What present-day state became part of the United States in the Mexican Cession (Treaty of Guadalupe-Hidalgo) at the conclusion of the War with Mexico? A) Oregon
B) Texas
C) California

Which statement best explains why a supreme court opinion is a seminal document? an opinion can become quite lengthy, which makes it a seminal document. supreme court documents are the only seminal documents in the united states. an opinion may create major changes in the laws or policies of the united states. generally speaking, a supreme court opinion reflects the feelings of all americans.