For decades, the Chinese Communist Party has been able to keep control of democracy protests, dissidents, the legal system and the military, but it is now facing an even more intractable foe: a plummeting stock market.

Invisible and fast-paced, mutinous market forces­ have defied the party-led government’s efforts to arrest the month-long slide in Chinese stock markets. If this continues, the slump in stock prices could slow the economy and undermine faith in the party’s leadership and power, experts on China and economics say.

Only three months ago, the state-run People’s Daily opined that rising stock prices were the “carriers of the China Dream” and affirmation of President Xi Jinping’s signature vision for what he calls the great rejuvenation of the Chinese nation. But what had been hailed as a bull market has turned into a burst bubble.

Shanghai’s main share index is down a third since its June peak. Trading in nearly three-quarters of listed shares was either frozen because of limit declines or completely suspended, and even the securities regulator was talking about a mood of “panic.”

As the stock market collapsed, Chinese authorities have ordered brokerages and insurers to buy, barred insiders from selling, and tapped the nation’s sovereign wealth to prop up shares. The government also invoked patriotism, blamed foreigners and arrested what it called rumormongers.

The Chinese stock swoon has been “a complete revelation of how unprepared the policymakers are for managing the transition to market-driven capital markets. That’s the question of the moment,” said Daniel Rosen, a partner at the Rhodium Group, a New York-based economic advisory firm. “The question for tomorrow is whether that immaturity applies to their ability to regulate other aspects of the economic transition as well.”

Xi’s aura of invincibility has taken perhaps its biggest hit since he came to power, experts say. While China’s economy can probably withstand the stock market crash, growth was already slowing and challenges continue to mount. The authorities’ clumsy response raises questions about their willingness to embrace tough economic reforms.

“The intervention comes with some real costs that will not be easy to overcome,” said Scott Kennedy at the Center for Strategic and International Studies in Washington. “The scale and aggressiveness of these measures make a mockery of the leadership’s claim to allow the market to play a ‘decisive role’ in determining the allocation of resources and the direction of the economy.”

Rosen added that the government “should not have maintained the support for markets once the inevitable correction began. They were spending their hard-won credibility in an effort doomed to fail.”

How the stock market collapse has been handled so far and how it is handled in the coming days goes to the heart of reform in an economy that is a strange mixture of robust private enterprise and a legacy of central planning.

For decades, some enthusiasts have argued that China was the exception to the rule: that its far­sighted leaders could make the transition to a more open economy while avoiding the debt trap that every other so-called miracle economy had fallen into since World War II. That idea could be the biggest casualty of the crash, both at home and abroad.

Investors look at computer screens showing stock information at a brokerage house in Shanghai. (Aly Song/Reuters)

“It is remarkable to us how analysts and investors around the world who deeply believe in the laws of economics and free markets have tacitly bought into the idea of Chinese exceptionalism,” wrote Anne Stevenson-Yang, director of J Capital Research.

Like many skeptics, Stevenson-Yang argues that China’s engineered “economy-by-fiat” is becoming ever more wasteful in its allocation of resources and that Xi’s grand vision of regional economic dominance through a New Silk Road economic area was an example of overreach.

Before peaking on June 12, China’s stock market had risen by about 150 percent in a year, completely divorcing itself from increasingly worrying economic and corporate fundamentals.

Frenzy gripped the nation; from high school students to farmers, ordinary Chinese citizens pooled ideas to take advantage of what looked like easy money. Thousands of people gathered in “street stock market saloons” in Shanghai from early afternoon until late in the evening to swap tips.

According to the state-run Xinhua News Agency, 90 million people, more than the membership of the Communist Party, had trading accounts.

Many people borrowed money to bet on an ever-rising market. By some accounts, the Chinese market became the most leveraged in history. But as the market has fallen, traders have been forced to unwind those leveraged positions and join the line of sellers.

The authorities responded first by easing monetary policy, suggesting pension funds would invest more, cutting trading fees and even relaxing rules of using borrowed money to speculate in the markets. Opinion leaders took to social media to demand that investors buy shares “for the nation.” Elderly women burst into trading halls to sing patriotic songs.

Then, with nothing working, they brought out the big guns. Last weekend, banks announced that the issuance of new shares through initial public offerings would be suspended, while 21 brokerages said they would contribute $19 billion to stabilize the market. The Shanghai composite index opened 7 percent higher Monday but immediately started to slide again.

The market’s decline has now wiped out more than $3.5 trillion in market value in a month. By comparison, the bursting of the dot-com bubble in the United States in 2000 caused a loss of $5 trillion.

When regulators posted comments on social media in an attempt to calm the market, they were greeted with thousands of abusive replies.

“I am not a 3-year-old. How many more times are you going to lie to me?” said one social media user. “This is how you treat your own people,” said another. “Give me my money back,” a third simply wrote.

Andrew Batson, the China research director at Gavekal Dragonomics in Beijing, said the scale of the government’s response was disproportionate to the scale of the problem. But having sold people on the idea that the market’s rise was an endorsement of its economic reforms and Xi’s vision of a “China Dream,” the government felt trapped, he said.

“It has made an implicit promise to a lot of people that the stock market will keep going up, so they feel the need to show the government can deliver on its promise,” he said.

Mufson reported from Washington. Gu Jinglu in Beijing contributed to this report.