Only a handful of peacetime politicians can claim to have changed the world. Margaret Thatcher, who died Monday, was one. She transformed not just her own Conservative Party, but the whole of British politics. Her enthusiasm for privatization launched a global revolution. And her willingness to stand up to tyranny helped to bring an end to the Soviet Union.

Winston Churchill won a war, but he never created an “ism.”

The essence of Thatcherism was to oppose the status quo and bet on freedom — odd, since as a prim control freak, she was in some ways the embodiment of conservatism. She thought nations could become great only if individuals were set free. Her struggles had a theme: the right of individuals to run their own lives, as free as possible from the micromanagement of the state.

In Britain, her battles with the left — especially the miners — gave her a reputation as a blue-rinse Boadicea. But she was just as willing to clobber her own side, sidelining old-fashioned Tory “wets” and unleashing her creed on conservative strongholds, notably the “big bang” in the City of London. Many of her pithiest putdowns were directed toward her own side: “U turn if you want to,” she told the Conservatives as unemployment passed 2 million. “The lady’s not for turning.”

Paradoxes abound. Thatcher was a true Blue Tory who marginalized the Tory Party for a generation. The Tories ceased to be a national party, retreating to the south and the suburbs and all but dying off in Scotland, Wales and the northern cities. Tony Blair profited more from the Thatcher revolution than did John Major, her successor. With the trade unions emasculated and the left discredited, Blair was able to remodel his Labor party and sell it triumphantly to middle England. His huge majority in 1997 ushered in 13 years of New Labor rule.

Yet Thatcher’s achievements cannot be gainsaid. She reversed what her mentor, Keith Joseph, liked to call “the ratchet effect,” whereby the state was rewarded for its failures with yet more power. With the brief exception of the emergency measures taken in the wake of the financial crisis of 2007-08, there have been no moves to renationalize industries or to resume a policy of picking winners. Thanks to Thatcher, the center of gravity in British politics moved dramatically to the right.

The New Laborites of the 1990s concluded that they could rescue the Labor Party from ruin only by adopting the central tenets of Thatcherism. “The presumption should be that economic activity is best left to the private sector,” declared Blair. Neither he nor his successors would dream of reverting to the days of nationalization and unfettered union power.

On the world stage, too, Thatcher continues to cast a long shadow. Her combination of ideological certainty and global prominence ensured that Britain played a role in the collapse of the Soviet Union that was disproportionate to its weight in the world.

Thatcher was the first British politician since Churchill to be taken seriously by the leaders of all the major powers. She was a heroine to opposition politicians in Eastern Europe. Her willingness to stand shoulder to shoulder with “dear Ronnie” to block Soviet expansionism helped to promote new thinking in the Kremlin. But her insistence that Mikhail Gorbachev was a man with whom the West could do business also helped to end the Cold War.

The postcommunist countries embraced her revolution heartily: By 1996, Russia had privatized some 18,000 industrial enterprises. India dismantled the license Raj — a legacy of British Fabianism — and unleashed a cavalcade of successful companies. Across Latin America, governments embraced market liberalization. Whether they managed well or badly, all of them looked to the British example.

But today the pendulum is swinging dangerously away from the principles Thatcher espoused. In most of the rich world, the state’s share of the economy has grown sharply in recent years. Regulations — excessive, as well as necessary — are tying up the private sector. Businessmen are under scrutiny as they have not been for 30 years. Demonstrators protest against the very existence of the banking industry. And with the rise of China, state control, not economic liberalism, is being hailed as a model for emerging countries.

For a world in desperate need of growth, this is the wrong direction to head. Europe will never thrive until it frees up its markets. America will throttle its recovery unless it avoids overregulation. China will not sustain its success unless it starts to liberalize. This is a crucial time to hang on to Margaret Thatcher’s central perception — that for countries to flourish, people need to push back against the advance of the state.

What the world needs now is more Thatcherism, not less.