People talk about transformational politicians. But watching Margaret Thatcher take down the British class system was an education in how it’s really done. It required the radical vision and iron will of someone who genuinely abhorred the status quo.

Thatcher demolished the two conservative pillars of British society: the labor unions that held the parliamentary Labor Party in bondage, and the upper-class Tory leaders who resembled the benign but hapless relics of “Downton Abbey.” It’s hard to say which side was more hidebound and resistant to change, the unions or the aristocrats. They were unwitting partners in Britain’s paralysis.

By breaking the power of the unions and the old Tory elite, Thatcher opened the way for a politically powerful British middle class. The universality of the middle class is America’s enduring national myth, so it’s hard for us to appreciate how narrow and precarious it was in Britain. Recall the disastrous aspirations for upward mobility of the bank clerk Leonard Bast in E.M. Forster’s novel “Howards End,” and you have a sense of the limited, dreary vista that was middle-class life before Maggie.

I had an unusual vantage on Thatcher’s revolution in British politics. I was a graduate student at Cambridge in 1974 and 1975, a time when the class-bound straitjacket of British politics was painfully evident, but still unbreakable. The Labor Party had returned to power at the end of the coal strike of 1974, a union-organized exercise in national suicide. Thatcher was seizing the leadership of a Tory Party dazed by defeat and seemingly in the wilderness.

The boundaries of British life were evident to my classmates. This was a time when many Cambridge students still seemed embarrassed about the idea of going into business. It was acceptable to be a professor, or a civil servant, or maybe at a stretch to take a financial job in the City of London. But, incredibly, a career in business was still regarded by most of my English friends as mere “trade.” If you couldn’t afford the country manor, better to live like a Bohemian.

The unions enforced the strict boundaries of life, too. When the coal strike of 1974 began, I journeyed to Wigan, the Lancashire mining town where George Orwell set his classic 1937 chronicle of class and society. I went down a mine, a mile underground, and saw the intense fraternity of the National Union of Mineworkers, which would brook no compromise in the strike. But I was even more struck by the townspeople of Wigan itself. There was no middle class to speak of; the very idea seemed like betrayal to the miners.

I wrote a freelance piece for The Washington Post’s Outlook section about what I’d seen. (It was my first byline in the paper.) The theme was how little had changed since “The Road to Wigan Pier.” Nobody understood the class system better than Orwell, who confided in the book that he was born into what he called the “lower upper-middle class.” In one memorable passage, he said that children of his youth had been taught: “The lower classes smell.”

I returned to London in 1980 as a young journalist. Thatcher had been elected prime minister the year before, and already you began to hear the early rumblings of what came to be known as “the big bang” that opened the financial sector to competition. Making money (as opposed to inheriting it) became fashionable. The power of the trade unions slowly eroded; the upper classes became porous; the new money could afford the fancy Belgravia townhouses and the country estates; and pretty soon people stopped asking who your parents were. Life became a Ralph Lauren ad.

The person who perfected the Thatcher revolution was Tony Blair. He guided what he called “New Labor” out of its union-enforced resistance to change. Soon after becoming party leader in 1994, he forced the old guard to drop Clause IV of the party constitution, which had committed it to the Leninist goal of “public ownership” of the economy, despite generations of reform efforts. That was the beginning of Labor’s renewal.

But it was Thatcher who opened the door for modern Britain. She wielded the wrecking ball that demolished old ideas and barriers, on the right and left. When people speak of Barack Obama or anyone else as a potentially transforming political leader, I ask myself: Does this person have the raw toughness and hunger for change of a Maggie Thatcher? Almost always, the answer is no.

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