Lincoln let the Confederate leaders know about his plan to resupply Fort Sumter so that they would not demand fire on the ships carrying supplies.
Answer: The act blocked Chinese immigrants from becoming American citizens.
Answer:
2) Refusing to join the League of Nations
Explanation:
The best action that demonstrated the United States' effort to isolate itself from European conflicts after World War I is "Refusing to join the League of Nations."
This is evident in the fact that the United States Congress failed to pass the bill to join the League of Nations. This is based on the idea or some Isolationists' fear that it might make the United States drawn into International issues unnecessarily.