Americans hate carpetbaggers. Hillary Clinton moves to New York; Scott Brown scoots across the state line to New Hampshire; Liz Cheney pretends to be from Wyoming. Uproar ensues.

In India, by contrast, the concept of carpetbagging doesn’t exist. On the contrary, for a smart politician like Narendra Modi, it can make a great deal of sense as a campaign strategy. Candidates can run wherever they choose, and Modi, who took office on Monday as India’s new Prime Minister, managed the unusual feat of being elected in two different constituencies. One was Vadodara, in his home state of Gujarat. For the other, he chose Varanasi, the holiest city in Hinduism. And, while his campaign stuck for the most part to sweeping generalities about prosperity and good governance, essentially vowing to replicate nationwide his success as chief minister of Gujarat, Modi did make one concrete, actionable promise: to clean up the grossly polluted Ganges, the most sacred stretch of which flows past the temples and cremation grounds of Varanasi.

The holy city and the sacred river. The man has a brilliant grasp of political symbolism.

Before his ascent in the right-wing, Hindu-nationalist Bharatiya Janata Party, the young Modi’s political ideas were formed by the B.J.P.’s parent organization, the Rashtriya Swayamsevak Sangh (RSS), whose founding fathers were admirers of European fascism. Charges that Modi acquiesced in the slaughter of more than a thousand Muslims in Gujarat in 2002 trail after him like a tin can tied to a dog’s hind leg. Yet these things seemed to bother foreign journalists more than they bothered Indian voters (with the notable exception, of course, of the country’s hundred and fifty million Muslims). Generally, the more unsavory aspects of Modi’s background and beliefs were drowned out by a disciplined campaign message of growth, jobs, and strong leadership. That message was tailored to resonate across all sectors of society, and it worked, stunningly.

Modi came late to Varanasi, announcing his candidacy in late March and filing the paperwork just two weeks before the city voted on May 12. (Given the mind-boggling logistics of getting half a billion people to the polls, Indian elections are staggered over a five-week period.) By then, everyone knew that Modi was going to win. The only question was by how much, and some of his most fervent supporters even saw the ultimate prize as being within his grasp—an absolute parliamentary majority, which no Indian leader has managed since Rajiv Gandhi’s landslide victory in the wake of his mother’s assassination, thirty years ago. So turnout became the key. Young Indians and the urban middle classes had already made up their minds. Now Modi turned up the volume on his populist appeal to the Hindu faithful and lower-caste voters who related to his own humble background as the son of a tea seller.

Varanasi is the fifth-largest city in the northern state of Uttar Pradesh. U.P., as it’s known, plays a disproportionate role in Indian politics. It was the birthplace of Jawaharlal Nehru, and it has been home to eight of the country’s fourteen Prime Ministers since independence. It’s also India’s most important state, in terms of its sheer size. U.P. has two hundred million people—roughly equal to the population of Brazil, but squeezed into an area thirty times smaller—and they’re some of the poorest people in India. U.P. is also notorious for corruption, and it has a particularly awful history of communal and religious violence. It was here, in 1992, that mobs spurred on by the B.J.P. and militant Hindu groups demolished a mosque in the town of Ayodhya, which some claimed had been built on the birthplace of the god Rama. Two thousand people died in the riots that followed. U.P. is also the heartland of caste politics, one of a handful of states where the support of powerful caste-based parties has been vital to the cumbersome coalitions that have defined Indian government for the past thirty years. So if Modi wanted an unfettered mandate, he had to sweep U.P.

His opponent in Varanasi was Arvind Kejriwal, the upstart anti-corruption campaigner who shocked the country when he was elected last year as chief minister of Delhi, only to flame out after forty-nine days in office. I happened to be in Varanasi at the end of March, when Kejriwal came to town to declare his candidacy. His inaugural rally was held—pointedly, I thought—in a large, dusty park in a heavily Muslim neighborhood. Tens of thousands showed up, many in white shalwar kameez and wearing the white knit kufi, the Muslim prayer cap. Kejriwal’s campaign slogan for Varanasi was “River, Weaver, Sewer”—“weaver” being the important code word, because the city’s sari-weaving industry is the economic mainstay of its Muslim minority.

Modi seemed to take it for granted from the outset that the Muslim vote was lost. He rarely spoke of them or to them, and never made the symbolic gesture of donning a kufi. But he went after Kejriwal in language that was anything but coded. As Kejriwal was speaking in Varanasi, Modi was holding his own rally in Punjab, close to the border with Pakistan. He started off by denouncing the AK-47 as the symbol of Islamic terrorism in disputed Kashmir. Then came his little joke: Kejriwal should be called “AK-49,” a play on his initials and the number of days he held office in Delhi. This was droll enough, I suppose, as far as it went. But in case anyone had missed his meaning, Modi spelled it out: Kejriwal was an “agent of Pakistan and enemy of India.” To anyone familiar with the violent history of the subcontinent since Partition, it’s hard to think of a more incendiary insult or a darker implied threat.

Modi hammered Kejriwal in the end, winning Varanasi by thirty-six percentage points. And he got his landslide in Uttar Pradesh, taking seventy-one of the state’s eighty parliamentary seats and wiping out the powerful caste-based Bahujan Samaj Party.

Last Saturday, Modi returned to Varanasi, and to the banks of the Ganges, to give thanks for his victory. Plunging into the labyrinthine back alleys of the old city, he visited the Kashi Vishwanath Temple, the “golden temple,” perhaps the most important shrine in all of Hinduism, and sprinkled Ganges water on the lingam of Lord Shiva. From there to the ghats, the steep steps that line the river, where pious Hindus yearn to be cremated in order to achieve moksha, liberation from the unending cycle of death and reincarnation. To the blowing of conch shells and the chanting of Vedic hymns, Modi joined in the Ganga Aarti, the nightly worship of the river. The Ganges is the river that cleanses all sins, and Modi reiterated his promise to cleanse the river in return, and “to begin cleansing India from Varanasi.”

Modi’s pledge to cleanse the Ganges isn’t just about metaphor, or religion, or stripping off the mask to reveal the dark side of his Hindu nationalism. It goes to the very heart of his appeal. Nothing sums up the failures of government in India better than the despoiling of the Ganges. Rajiv Gandhi vowed almost thirty years ago to clean it up. Since then, hundreds of millions of dollars have been squandered on his Ganga Action Plan, with no discernible results. Some of the most noxious chemical effluent in the world still flows into the Ganges from the tanneries of Kanpur, two hundred miles upstream from Varanasi, because there are no effective treatment plants. Raw sewage still pours into the river because pumping stations are regularly shut down by power cuts. Fecal coliform bacteria levels along the ghats of Varanasi, where pilgrims take their “holy dip,” are off the charts.

Not all of this can be blamed on the ineptitude and corruption of the central government. State authorities like those in U.P. share the blame. India’s ruling coalitions bog down in large part because they depend on the support of these often rotten and incompetent regional fiefdoms. And state governments have the primary responsibility for things like sewage-treatment plants. The real significance of Modi’s landslide is that he can rule without any of these restraints, which is, in any case, his temperamental preference. His clean-up-the-Ganges campaign, then, becomes a kind of litmus test for his vision of efficient, if authoritarian, government. That’s what he claims to have accomplished in Gujarat, and it’s what voters now demand and expect of him.

George Black is writing a book on the history and culture of the Ganges.

Photograph by Roberto Schmidt/AFP/Getty.