In his resignation speech following Great Britain’s vote to divorce from the European Union, Prime Minister David Cameron claimed several achievements by his government: reforming welfare and education, increasing development assistance to “the poorest people in the world” and “enabling those who love each other to get married, whatever their sexuality.” He also mentioned “building a bigger and stronger society” — a reference to his “Big Society” ideological framework, which sought to empower local people and communities as an alternative both to centralized bureaucracies and to libertarian indifference.

What is remarkable about Cameron’s definition of success is how utterly disconnected it is from the deep, visceral populist trends that have come to dominate his party and now his country. Cameron had attempted to define a post-Thatcherite conservative vision “integrating the free market with a theory of social solidarity.” But this was swept away, not so much by an alternative argument — the economic case against the Brexit is overwhelming — but by powerful, ethno-nationalist instincts. In retrospect, Cameron’s project of ideological renovation was hopeless, even poignant — trying to organize an outdoor tea during a hurricane.

For American conservatives, this is the most frightening aspect of the British vote. Since 1955, with the founding of National Review, conservatives have attempted to make ideological arguments ­— involving respect for free markets and civil society — that they hoped would win influence in the United States’ center-right party. But now that entire project seems threatened.