An anticorruption campaign has given voice to a growing middle class tired of public indignities

A year ago, no one in India could have imagined that cabinet ministers, powerful politicians, senior officials and CEOs would be in jail now, awaiting trial for corruption. The credit for this dramatic shift belongs in no small part to the anticorruption movement of a 74-year-old activist, Anna Hazare, supported by determined justices of the Supreme Court, an exceptional auditor general, rival television channels in search of "breaking news" and, crucially, a newly assertive Indian middle class. The long-term impact of this movement is unclear. It could lead to something profoundly good, or it could destabilize the whole system.

A series of corruption scandals has swept India over the past year. These include graft-ridden purchases for the 2010 Commonwealth Games in Delhi, for which rolls of toilet paper were purchased for $80 each; the government's sale to favored companies of licenses for the mobile-phone spectrum, at prices so low that they are estimated to have lost taxpayers somewhere between $10 billion and $40 billion; and the grabbing of expensive apartments in Mumbai by politicians, officials and generals on prime property that was meant for war widows.

Fighting this pervasive corruption has been Mr. Hazare, a villager in a white rural cap who evokes the figure of Mahatma Gandhi and has successfully emulated Gandhi's protest tactics of hunger strikes and peaceful marches. Mr. Hazare launched his first hunger strike, a five-day fast, in April. As a result, the government agreed to draft a bill creating an anticorruption agency that would investigate complaints against officials, but the bill was weak, and Mr. Hazare rejected it.

His second hunger strike, which he staged last month in Delhi, drew tens of thousands of supporters and spurred the government to agree to discuss his own version of the bill—a considerable victory, since politicians of all parties have stonewalled the creation of an anticorruption agency for 40 years.

Many officials were taken by surprise by Mr. Hazare's support from the middle class, which is almost a third of India's population today, up from 8% in 1980. Since reforms in 1991, India has become the world's second-fastest-growing economy, and the middle class is expected to become 50% by 2022.

There are still vast areas of horrible deprivation, but a significant number of Indians have experienced a palpable betterment in their lives. As a result, the discourse of the nation, or what Alexis de Tocqueville called "habits of the mind," are changing. People have begun to believe that their future is open, not predetermined, and can be altered by their own actions.

The same thing happened in the West after 1800. In her book "Bourgeois Dignity: Why Economics Can't Explain the Modern World," Deirdre McCloskey argues that the West rose not only because of economic factors but because the discourse about markets and innovation changed. People became encouraging of entrepreneurs. New perceptions and expectations emerged.

In the same way, the rise of India and China has brought dignity to their middle classes. Ordinary conversations over chai in India are now about markets and focus on the contrast between private success and public failure. While the private sector provides cutting-edge services and products to the world, the roads outside are potholed, electricity is patchy and water supply erratic. The difference between the two worlds is accountability: In private life, if you don't work, you don't eat; in public life, jobs are effectively for life. Indians believe that they are rising despite the state and are often heard to say that "India grows at night, when the government sleeps."

India's electoral politics do not cater to this aspiring middle class. Every party treats the voter like a victim, focusing on welfare programs or historical wrongs. Politicians have not realized that with high growth, mobility and a demographic revolution, aspiring Indians will soon overtake those who see themselves as victims. The person who got India's 851,695,668th cellphone in June was a village migrant, and no one in the country's political life captures his hopes. An op-ed about Mr. Hazare's protest movement in the Times of India had just the right title: "It's the middle class, stupid."

For too long Indians have been denied dignity by public officials who ride in cars topped with flashing lights and make citizens wait endlessly in gloomy offices, placing miles of red tape in their way to get even basic documents. The newly assertive middle class will no longer put up with this. As the social anthropologist Shiv Vishwanathan says, "The consumer revolution that we have experienced in the past two decades has told the citizen that he can expect a higher quality of governance."

It would be a shame if Mr. Hazare's movement contributed to undermining India's finely crafted constitutional system, which has made its democracy the envy of the developing world. Street protests and hunger strikes can gain attention, but legislation requires working within the system, in the messy details of parliamentary negotiation.

Mr. Hazare's bill is needed medicine, but it is being administered long after the sickness appeared. Clearing swamps is a better way to tackle malaria than administering quinine.

To prevent day-to-day corruption, Mr. Hazare and others like him need to work on reforming the rules of India's bureaucracy—creating transparent decision making, reducing discretion, shrinking opportunities to manipulate public rules for private gain and penalizing delays (the favored tactic of a corrupt bureaucrat). Indian bureaucracy needs to be transformed from a system based on the benefits of seniority to one that rewards good performance and punishes poor outcomes.

India's churning reflects a deep middle-class anger with pervasive graft in the government, police and judiciary. Bourgeois dignity may well hold the key to this Indian puzzle, but it needs to find expression within the bounds of the country's constitutional system. Street theater seldom makes for lasting reform—and sometimes brings down the good with bad.

—Mr. Das is the author of "The Difficulty of Being Good" and "India Unbound."