How the Iron Lady Fell Down the European Rabbit Hole

Understanding Britain’s Ambivalence Toward the Continent Starts With Margaret Thatcher, Who Backed Integration Before Deeply Regretting It

Make a list of the worst crimes anyone can commit and matricide has to come very near the top. Yet that’s what Britain’s Conservative Party committed a quarter of a century ago. Understanding this is the key to understanding why, this summer, the U.K.’s Conservative government is holding a referendum which could see the country bolt from the 28-member European Union.

In November 1990, Margaret Thatcher had been the Conservative Party’s leader for 15 years and had never lost a general election. Indeed, as her strongest supporters never tired of …