Was the United Nations the organization shaping interwar enforcement?
Short answerNo. It was the League of Nations, and it lacked force when the United States stayed out and Britain and France would not or could not enforce its decisions.
NotesThe interwar organization was the League of Nations, not the later United Nations. Although Woodrow Wilson's Fourteen Points shaped the League, the US Congress kept the United States out. The institution therefore depended heavily on Britain and France to turn decisions into action. If treaty constraints and weak defenses left those states unwilling to enforce a ruling, the League became a forum without coercive power. The later UN Security Council offers a comparison for similar veto and enforcement limits.