American Involvement in European Security: Necessary or Not?

This research examines the extent to which United States involvement influences the success and durability of European Union Treaties and Agreements. Understanding this role is critical as EU strategic autonomy has increased in recent decades in the hope of maintaining transatlantic cooperation. Existing literature often measures this impact in a culmination of NATO, rather than the United States specifically. By isolating the United States involvement, this research provides significant evidence for how an individual “hegemonic” power can influence the decision-making and institutional structure of an international organization. Using a comparative study qualitative approach, this research analyzes five agreements from 1990 to 2023: The Treaty of Maastricht, the Treaty of Amsterdam, the Treaty of Lisbon, the Berlin Plus Arrangements, and the U.S.-EU Energy Security Agreement. Treaty success is measured through institutional durability, additional amendments, and implementation outcomes throughout the European Union and abroad. I argue that the United States' involvement in EU National Security treaties will increase its success when the United States is involved using military or diplomatic interests. When the United States has economic and trade involvement in these treaties, they are less likely to be successful, as the US is using them greatly for its benefit.