This is an excerpt from a speech given by President Theodore Roosevelt. Based on this speech, what philosophy influenced America's imperialistic policy? The United States had the responsibility to intervene in the affairs of countries deemed to be weaker and less developed. The United States had the responsibility to intervene in the affairs of countries deemed to be weaker and less developed. For its own safety, the United States should avoid interfering in countries involved in internal conflicts. For its own safety, the United States should avoid interfering in countries involved in internal conflicts. To promote economic growth, the United States should encourage trade with other industrialized nations. To promote economic growth, the United States should encourage trade with other industrialized nations. The United States needed to annex nations that are unable to govern their own people effectively.