THE former C.I.A. analyst Paul R. Pillar asked this question in a recent essay in The National Interest: Why are we seeing so many popular street revolts in democracies? Speaking specifically of Turkey and Brazil, but posing a question that could be applied to Egypt, Israel, Russia, Chile and the United States, Pillar asks: “The governments being protested against were freely and democratically elected. With the ballot box available, why should there be recourse to the street?”

It is an important question, and the answer, I believe, is the convergence of three phenomena. The first is the rise and proliferation of illiberal “majoritarian” democracies. In Russia, Turkey and today’s Egypt, we have seen mass demonstrations to protest “majoritarianism” — ruling parties that were democratically elected (or “sort of” in Russia’s case) but interpret their elections as a writ to do whatever they want once in office, including ignoring the opposition, choking the news media and otherwise behaving in imperious or corrupt ways, as if democracy is only about the right to vote, not rights in general and especially minority rights.

What the protesters in Turkey, Russia and Egypt all have in common is a powerful sense of “theft,” a sense that the people who got elected are stealing something more than money: the people’s voice and right to participate in governance. Nothing can make a new democrat, someone who just earned the right to vote, angrier.

Here is what the satirist Bassem Youssef, the Jon Stewart of Egypt, wrote in the Egyptian daily Al Shorouk last week, on the first anniversary of the election of President Mohamed Morsi of the Muslim Brotherhood’s party: “We have a president who promised that a balanced constituent assembly would work on a constitution that everyone agrees on. We have a president who promised to be representative, but placed members of his Muslim Brotherhood in every position of power. We have a president and a party that broke all their promises, so the people have no choice but to take to the streets.”

A second factor is the way middle-class workers are being squeezed between a shrinking welfare state and a much more demanding job market. For so many years, workers were told that if you just work hard and play by the rules you’ll be in the middle class. That is just not true anymore. In this age of rapid globalization and automation, you have to work harder, work smarter, bring more innovation to whatever job you do, retool yourself more often — and then you can be in the middle class. There is just so much more stress on people in, or aspiring to be in, the middle class, and many more young people wondering how they’ll ever do better than their parents.

Too few leaders are leveling with their people about this shift, let alone helping them navigate it. And too many big political parties today are just vehicles for different coalitions to defend themselves against change rather than to lead their societies in adapting to it. Normally, this would create opportunities for the opposition parties, but in places like Turkey, Brazil, Russia and Egypt the formal opposition is feckless. So people take to the streets, forming their own opposition.

In America, the Tea Party began as a protest against Republicans for being soft on deficits, and Occupy Wall Street as a protest against Democrats for being soft on bankers. In Brazil, a 9 cent increase in bus fares set off mass protests, in part because it seemed so out of balance when the government was spending some $30 billion on stadiums for the Olympics and the World Cup. Writing in The American Interest, William Waack, an anchorman on Brazil’s Globo, probably spoke for many when he observed: “Brazilians don’t feel like their elected representatives at any level actually represent them, especially at a time when most leaders fear the stigma of making actual decisions (otherwise known as leading). … It’s not about the 9 cents.”

China is not a democracy, but this story is a sign of the times: In a factory outside Beijing, an American businessman, Chip Starnes, president of the Florida-based Specialty Medical Supplies, was held captive for nearly a week by about 100 workers “who were demanding severance packages identical to those offered to 30 recently laid-off employees,” according to Reuters. The workers feared they would be next as the company moved some production from China to India to reduce costs. (He was released in a deal on Thursday.)

Finally, thanks to the proliferation of smartphones, tablets, Twitter, Facebook and blogging, aggrieved individuals now have much more power to engage in, and require their leaders to engage in, two-way conversations — and they have much greater ability to link up with others who share their views to hold flash protests. As Leon Aron, the Russian historian at the American Enterprise Institute, put it, “the turnaround time” between sense of grievance and action in today’s world is lightning fast and getting faster.

The net result is this: Autocracy is less sustainable than ever. Democracies are more prevalent than ever — but they will also be more volatile than ever. Look for more people in the streets more often over more issues with more independent means to tell their stories at ever-louder decibels.