On Monday night, JD Vance appeared on Sean Hannity’s Fox show to declare a Zeitenwende in US foreign policy: from the idealism of the neoliberal era to a structural realpolitik attuned to the constraints of American and European power.

The Vice President’s clash with Volodymyr Zelensky in the Oval Office has dominated geopolitical conversations since Friday, and Vance emphasised throughout his Hannity appearance that he and Trump were not looking for fireworks with the Ukrainian leader. Vance also hammered home to the Fox host the necessity of some kind of peace deal.

But perhaps most revealing was the VP’s implicit argument for why some ceasefire had to be obtained. Geopolitics during the presidencies of Bill Clinton, George W. Bush and Barack Obama was often seen through a normative lens: what should be done? In contrast to that normative approach, Vance insisted on the sheer practical unsustainability of the Ukraine conflict. For him, the war was not a question of “values” but instead blood, cash, and steel. As he put it: “Fighting forever with what? With whose money, with whose ammunition, and with whose lives?”

Contemporary populism has been forged in the fires of disappointment — from debacles abroad to a financial crisis at home — so populist leaders like Trump and Vance have often emphasised the limits of projecting American power abroad. Vance’s invocation of money, ammunition, and lives underlines some of the hard constraints upon both American and European policymakers. For decades, many Nato security partners have underinvested in their militaries. As recently as 2021, Germany was spending under 1.5% of its GDP on defence, while most Nato countries spent barely more than 2% just last year. The Biden White House projected that American defence spending as a percentage of the national economy would itself decline over time — even as it was committing the United States to open-ended support for Ukraine. Needless to say, that is not a sustainable trajectory.