The sense is that even Indian Muslims, particularly in border states, may fall through the N.R.C. cracks if they cannot produce the documents required, while Hindus, Sikhs, Buddhists, Christians and Zoroastrians can claim citizenship through the new citizenship law. Mr. Modi’s party has always maintained that only Hinduism, Sikhism, Jainism and Buddhism are Indian religions. The inclusion of Christians on the list of acceptable communities in the new law is seen as a peace offering to influential Christian groups in the West.

It was against this fraught backdrop on Dec. 13 that students at two major public universities, Jamia Millia Islamia in Delhi and Aligarh Muslim University in neighboring Uttar Pradesh, held protests against the new law. Both universities have significant Muslim student populations and histories linking them to Muslim social reform movements and India’s independence movement. The protesting students spoke of equal citizenship; the government saw troublesome, young Muslim bodies on the street and unleashed the police upon them.

At Jamia Millia Islamia, the police stormed the campus, exploded tear-gas canisters inside the library, smashed everything in sight and battered students with their bamboo staffs, before marching them out onto the street with their hands up in the air. Police brutality left a student blind in one eye and many with broken bones. At Aligarh Muslim University, about 85 miles southwest of Delhi, police brutality was at an even higher level. Tear gas canisters were fired into student dorms. Scores were injured, battered by police with heavy bamboo staffs and rifle butts. At least two students are in critical care with head injuries, and two had their hands blown off by stun grenades fired by the police.

Prime Minister Modi sought to discredit the protests as violent and deployed his usual sectarian dog whistle. “Those creating violence can be identified by their clothes,” Mr. Modi said. Every Indian heard that as a reference to Muslims, to the skull caps and shalwar kameez, a knee-length, long-sleeved shirt with a pair of loosefitting trousers that Muslim men in northern India wear. Mr. Modi, his party and the broader Hindu nationalist movement have worked tirelessly to redefine India as a majoritarian Hindu nation and cast India’s Muslims, secular intellectuals, liberals, progressive universities, respected former prime ministers, vice presidents and anyone who disagrees with their politics, including the political opposition, as the “enemy within.”

The brutal police action against students at Jamia Millia Islamia and Aligarh Muslim University, a majority of whom are Muslim, seemed calculated to peddle stereotypes of violent Muslims and to terrorize India’s Muslims, once again, into silence, by criminalizing their best and brightest.

But for the first time in years it seems silencing people may not be so easy. What followed the police violence was not acquiescence but an inspiring assertion of citizenship and solidarity by tens of thousands of young, educated Indians in universities and colleges across the nation.

Even campuses known for their political and social conservatism, like the Indian Institutes of Technology and the Indian Institutes of Management, held vigils and signed petitions against the new citizenship law or in support of Jamia and Aligarh students, sometimes defying hostile college administrations.