Thousands nationwide have protested against India’s new citizenship law in recent days, facing a brutal police response. This is arguably the biggest display of opposition to Narendra Modi since he took power six years ago, and for good reason. Demonstrators have been urged into action not by the sense of a new direction being established, but of the confirmation of the country’s alarming trajectory. The legislation is the proof that Mr Modi’s Hindu nationalist project is not a containable anomaly, but an enterprise that threatens the nation’s very foundations of pluralism and secularism. Fear overshadows the hopes of that seven-decade endeavour.

The prime minister has piously tweeted: “This is the time to maintain peace, unity and brotherhood.” Superficially this is, as the BJP government claims, a law that expands rather than removes rights. It creates a fast-track path to citizenship for Hindus, Sikhs, Jains, Buddhists, Parsees and Christians arriving from Muslim-majority states, who would otherwise spend years labelled as illegal immigrants. But no one considering either its text or context could seriously regard this as a measure of inclusion. It is inherently one of exclusion, which discriminates against Muslims fleeing persecution, and signals that Muslim citizens are not “truly” Indian. It undermines constitutional protections which apply to foreigners as well as citizens in India.

The purported logic is that Muslims do not need India’s help – news to Rohingya Muslims from Myanmar and Ahmadis and others in Muslim Pakistan. Should they arrive in Mr Modi’s country they will be simply illegal immigrants. In a country where many lack proper documentation, Indian citizens risk the same status.

Look to north-eastern Assam, where almost two million people face statelessness following exclusion from the National Register of Citizens, sometimes because of simple clerical errors. Citizens have been turned into foreigners. Detention centres are already under construction. The home affairs minister, Amit Shah, has compared illegal immigrants to termites and says India will not allow a single one to stay.

A country-wide version of the NRC has repeatedly been proposed. Meanwhile the Muslim-majority state of Kashmir remains under lockdown after the government removed its special status, which had been an emblem of India as a multifaith nation. Lynchings by Hindu nationalists have risen sharply under Mr Modi. That the legislation is deepening communal divides is not accidental. The prime minister’s claim that those setting fires “can be identified by their clothes” was read as a clear reference to Muslims. It is the rankest hypocrisy to accuse others of spreading violence, even if it were possible to set aside Mr Modi’s record as the former chief minister of Gujarat when around 2,000 Muslim men, women and children were murdered.

Figures in the west as well as at home helped to rehabilitate him after the 2002 pogrom, lauding him as a dynamic economic reformer. But his disastrous demonetisation in 2016, which cost at least 1.5m jobs, put paid to the idea of trading on that idea. His failures in dealing with the country’s real problems – economic growth is slowing dramatically and unemployment at a four-decade high – have not created his majoritarianism. But they have spurred it.

The prime minister’s extraordinary political success reflects both his deeply-rooted ideological instincts and his utter opportunism. Having crushed the Congress party in May’s elections, he has another five years in power, and few obstacles in his path. There can be no doubt about where that path is leading. The legislation, warns the noted scholar Pratap Bhanu Mehta, is a giant step towards converting a constitutional democracy into a unconstitutional ethnocracy. The question is only how many more such steps India takes, and how fast.