The world got to know Narendra Modi in 2015. India’s prime minister visited more than two dozen countries last year, collecting more passport stamps than any of his peers. The sellout crowds of Indian expats and immigrants in London, Toronto, Silicon Valley and elsewhere created the impression of an ascendant nation led by an unassailable prime minister. Modi’s India matters in a way that the country led by his predecessor, Manmohan Singh, did not.

Back home, the story is a little different. Modi looms large; his approval ratings exceed 70 per cent. But the prime minister’s popularity is being tested by an individual who is doing to the Indian establishment what Modi is doing to international order: disrupting it.

Arvind Kejriwal, a public-servant-turned-agitator-turned-politician, is about to mark the anniversary of a remarkable victory. A year ago, he and his upstart Aam Aadmi Party (AAP) won 67 of 70 seats in the Delhi assembly, handing administrative control of India’s capital, New Delhi, to a band of rabble rousers.

It was a humbling loss for Modi’s Bharatiya Janata Party (BJP). Its candidates had swept Delhi in the national election less than a year earlier. It also was a blow to Congress, the former national governing party, which went from running the assembly to having no representation at all. Kejriwal’s earnest pledge to “sweep” corruption out of government and to help Delhi’s poorest appealed to voters, especially younger, aspirational ones. “He is upsetting the cosy status quo,” says Manjeet Kripalani, a former journalist who co-founded Gateway House, a think tank based in Mumbai.

Kejriwal used his first year to strip the Delhi rulebooks of opportunities to squeeze citizens for cash and to start the process of expanding public health coverage. His biggest success came earlier this month when an experiment in traffic rationing in New Delhi went surprisingly well; millions of drivers who routinely ignore stop lights and lanes were somehow convinced to park their cars every other day to try to reduce smog in the world’s most polluted city.

Yet Kejriwal is known at least as much for picking fights with Modi and the central government, which controls some aspects of Delhi adminstration, including the police. These tantrums have made him vulnerable to ridicule and political attacks. In early January, Goonj Labs, a Mumbai-based research firm that trawls the Internet to identify social trends, released a report that declared Kejriwal was the “most hated man in India” in 2015.

There were some who predicted Kejriwal would fade, if only because India’s ruling class has a way of making wannabe usurpers go away. Hardik Patel, a young firebrand from Gujarat, the state Modi ran for more than a decade before he became prime minister, became an overnight political sensation last summer. He rallied tens of thousands of Patels to demand a share of the government jobs and college placements set aside by law for disadvantaged castes. (The Patel clan is comfortably middle class by Indian standards.) Newspapers started talking about Patel as a threat to Modi’s dominance. But Patel’s rhetoric became increasingly violent; he urged a crowd in New Delhi to “speak with swords instead of garlands.” A subsequent gathering in Gujarat sparked a deadly riot. Patel is now in jail on charges of sedition.

Kejriwal avoids violent imagery. But he does share Patel’s penchant for hyperbole and melodrama. In December, Kejriwal called Modi a “coward” and a “psychopath.” Such outbursts are common and there is evidence that some Indians may be tiring of them. “He is self-centred, egocentric and he does not brook any opposition to his plans, ideas or actions,” says Satish Misra, a senior fellow at the Observer Research Foundation, a think tank in New Delhi.

Indrashil C Rao, a retired vice-admiral in the Indian Navy and an AAP supporter, says his leader has “good points and bad points.” Petulance, Rao concedes, is among the bad ones. Last week, while Kejriwal was giving a speech in New Delhi marking the completion of his smog-fighting plan, an angry woman pushed through a crowd and flung ink at him. An AAP official called the attack a rehearsal for an assassination attempt.

If there is a backlash against Kejriwal, it is at least partially manufactured by his political rivals. The Goonj survey was only semi-serious, as its authors conceded there is little they can do to control for the partisan smear campaigns that have come to characterize life on social media in India. The BJP is by far India’s most effective political organization and its rank-and-file members are extremely protective of Modi, especially online, where a militia of partisans lies in wait for anyone who criticizes their leader.

To have irritated so many Internet trolls, without having killed any babies or harmed any kittens, suggests that Kejriwal may be doing something right. “Both the BJP and the Congress fear the AAP because Kejriwal has made no secret of his plan to expand his party countrywide,” Misra says. Rao says Indians are drawn to the AAP because they are “sick of these old parties” that have created a country that is tied for 85th on Transparency International’s corruption index.

In 2014, the political establishment thought it had crushed the AAP. The party was born out of a broad anti-corruption movement that gained force over the final years of the previous Congress government, which was drowning in scandals. The AAP was barely a year old when it stunned pundits by winning enough seats in the Delhi assembly to form a minority government. Kejriwal, with virtually no experience in formal politics, became chief minister. This was December 2013. Less than two months later, Kejriwal abruptly resigned to contest the national elections. Kejriwal made an ill-fated decision to run in Modi’s district. The AAP itself won only four seats, all of them in the northern state of Punjab. The BJP won 282 of 543 seats in India’s lower house of parliament, the Lok Sabha.

Modi told voters in that election that he would need two five-year terms to change the country. The safe bet today is that he will get a second one. No politician with his approval ratings is in imminent danger and the opposition is still demoralized by the shellacking it received two years ago. Congress, run by the mother-and-son team of Sonia and Rahul Gandhi, still controls the upper house of parliament, a position the Gandhis have used to bring Modi’s legislative agenda to a standstill. Polls suggest this tactic has only further eroded the party’s popularity.

Two political rivals united in Bihar last autumn to repel a push by the BJP to add another state to its collection. But it is far from clear whether that model will translate nationally, as there is no obvious candidate to unite India’s various regional factions. The BJP could just as easily draw powerful local leaders to its side.

Kejriwal is a wild card. He still may be green, but he is no longer without experience in government. Misra of the Observer Foundation says Kejriwal has been overly political, cluttering the capital with propaganda posters, currying favour with the poor, and unfairly maligning the police and the central government. But Kejriwal has also had successes. For instance, he scrapped a policy that allowed senior ofﬁcials to reserve nursery school spaces, a privilege that for years had been an invitation to corruption.

The question for Kejriwal—and for Modi and the BJP—is whether the AAP’s anti-establishment message will resonate beyond Delhi. Kripalani of Gateway House says it will take years for the AAP to become a national force, but that it is possible because unlike so many others, Kejriwal has found a way to translate the anger at the injustices of the global financial crisis into enough votes to win elections.

Earlier this moth, the AAP leader went to Punjab to launch his party’s campaign for next year’s assembly elections. The established political powers in the state also held rallies. All of them ridiculed Kejriwal, even though doing so only legitimized him as a threat. But Kejriwal has that effect on people. He can’t be ignored.