This report assesses domestic political support for internationalist foreign policy by analyzing the motivations of members of Congress on key foreign policy issues. It includes case studies on major foreign policy debates in recent years, including the use of force, foreign aid, trade policy and U.S.-Russia relations. It also develops a new series of archetypes for describing the foreign policy worldviews of members of the 115th Congress to replace the current stale and unsophisticated labels of internationalist, isolationist, hawk and dove. Report findings emphasize areas of bipartisan cooperation on foreign policy issues given member ideologies.