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.
