As Communist Chinese authorities tear-gas the millions protesting for freedom in the streets of Hong Kong, we can’t help but wonder what Margaret Thatcher might be thinking. She’s gone, of course, and we nurse no doubts that she was, and will always be, one of the 20th century’s heroines. Yet what is the Iron Lady thinking in the purgatory that must be traversed by free leaders who treat with communists?

Thatcher was the British prime minister who, in 1982, launched, with China’s Communist Party boss, Deng Xiaoping, the negotiations that would seal the fate of the British Crown Colony. Britain was in a tight spot, for sure. Its lease on the vast majority of Hong Kong, the New Territories, would expire in 1997. It had, though, permanent sovereignty over the core of the Crown Colony.

The treaty Mrs. Thatcher inked — the Sino-British Joint Declaration of 1984 — gave up that permanent possession in return for a promise. It was known as “one country, two systems.” China would get Hong Kong, but Hong Kong would get to develop its freer system for 50 years. It was, in essence, a gamble that China could so reform its system that eventually it would be prepared to tolerate democracy.

Almost immediately it became clear that it was a vain hope. Experienced veterans of the Cold War had always warned that the Communists, being Communists, would betray their promise. China’s Party began moving against democracy at every turn, including in the crafting of a basic law, or mini-constitution, to govern Hong Kong in its 50-year transition.

The current crisis was triggered by a galling gambit from Beijing — proposed legislation to permit Hong Kong persons to be extradited for trial and punishment in Communist China, where there is no due process in the sense that Hong Kong experienced under British rule. So the streets are filled with protesters in their millions, many born well after Red China took over.

Which brings us back to Mrs. Thatcher. Though she put up a brave front, she was extremely sensitive to criticism that she had failed Hong Kong. After she left office, she met with the editors of the Wall Street Journal, which had once issued a devastating editorial called “Maggie’s Honor.” She lit into them something fierce, before leaning across the table and demanding, “Do I make myself cleee-ah?”

The Journal’s editor, Robert Bartley, didn’t bat an eye. He knew, we once wrote, that Mrs. Thatcher knew that the newspaper’s editorials on Hong Kong were as right as rain. Which, by our lights, is the thing to keep in mind in the current crisis. This is a moment to learn from her travail. It is no moment — not that there ever was one — for appeasement in respect of the Chinese Communists.

It’s not just Hong Kong, after all, though the former British Crown Colony would be enough. The crackdown on Hong Kong is part of a broader campaign by the Chinese Party boss, Xi Jinping. His regime is also rounding up the Uighurs into camps, moving broadly against Christians and their churches, and crushing Tibet. It is extending its military perimeter into the South China Sea.

This is a moment to remember that the kind of violence we’re witnessing in Hong Kong is the only foundation of communist rule in China and elsewhere. It’s a moment to remember the only real democracy in China is the free Republic of China on Taiwan, where the Legislative Yuan once maintained seats for every province on the mainland. It’s the best route to redeem Margaret Thatcher’s bet.