The Progressive Era is considered from 1890 to 1920. The major role of the United States in global affairs during this period of time was its involvement in the war.
The military affairs of that time included the war with Spain, the war to conquer the Philippines and the entry into the First World War.
Until the beginning of the 20th. century, political affairs in the US used to follow Washington and Madison, guidelines of neutrality and nonintervention.
But in those times, European nations turned into imperialism, establishing colonies in different parts of the planet. Time passed by when Theodore Roosevelt, influenced by <em>The Influence of Sea Power Upon History</em>(written by Admiral Alfred Thayer in 1890), understood the potential of investing money in other countries, securing the interest of the U.S.
In the 1910-1920's, the United States government followed an intervention policy in the Caribbean and Central America, the Philippines and even President Wilson supported the Mexican revolution.
From what I can remember, states' rights was a large factor contributing to the Civil War. With Lincoln becoming president and representing the North, the Southern states seceded, leading to a war. The state governments of the South argued that since the Constitution and the federal government was created by the states, the federal government had no right to stop states from seceding. President Lincoln and other northerners disagreed and wanted to preserve the Union by stopping states from seceding.
After the war, I believe the South still disagreed on a strong federal government. They wanted to rule the area by themselves.
Answer:
have to be letter A. My Lai Massacre