How Threats of American Withdrawal from NATO Affect European Public Attitudes Toward Defense

Abstract How does the threat of a dominant ally withdrawing affect public attitudes toward defense spending and defense cooperation in alliances? Despite extensive literature on foreign policy attitudes, we lack research that causally examines this pivotal question in a realistic setting. Addressing this gap, we utilize the novel circumstances surrounding the coin-toss 2024 US presidential election to test how the unprecedented uncertainty of the US commitment to NATO affects public attitudes toward defense in allied countries. Using a preregistered survey experiment in the United Kingdom, Sweden, and Germany, we investigate how an uncertain election defined by contrasting candidate rhetoric influenced European public opinion in an era of renewed Russian military threats. We find that US threats of withdrawal made respondents significantly more willing to spend on defense, and less willing to support continued defense cooperation in NATO. We demonstrate that threats of withdrawal also increased the public’s preference for national security autonomy, and explore whether declining confidence in NATO allies explains this effect. By inciting fears of abandonment, threats of withdrawal create concrete consequences not only for defense spending preferences, but also the types of cooperation that allies may pursue in lieu of the dominant ally’s commitment.