U.S. Role in the World: Background and Issues for Congress [Updated October 23, 2019] [open pdf - 1MB]
From the introduction: "This report provides background information and issues for Congress regarding the U.S. role in the world, meaning the overall character, purpose, or direction of U.S. participation in international affairs and the country's overall relationship to the rest of the world. The U.S. role in the world can be viewed as establishing the overall context or framework for U.S. policymakers for developing, implementing, and measuring the success of U.S. policies and actions on specific international issues, and for foreign countries or other observers for interpreting and understanding U.S. actions on the world stage. Some observers perceive that after remaining generally stable for a period of more than 70 years (i.e., since the end of World War II in 1945), the U.S. role in the world under the Trump Administration is undergoing a potentially historic change. A change in the U.S. role in the world could have significant and even profound effects on U.S. security, freedom, and prosperity."
CRS Report for Congress, R44891
Congressional Research Service: https://crsreports.congress.gov/