Im not sure but I think it was the beginning of modern warfare.
Answer:
B. They did not want slavery to extend to new areas of the United States.
Explanation:
The abolitionists didn't want to support the Mexican-American War because they did not want another slave state, in this case, Texas. War was always supported by both sides.
They thought in another slave state like political instability in the United States, but they thought that there were more benefits about the war, and Texas was become in the 28° state of the United States and also in another state slave.
