NEW DELHI -- Arun Shourie is a quiet man who runs a very loud newspaper. In the cool stillness of his office at the Indian Express, he quotes Robert Kennedy and Thomas Paine in a whispery voice. Outside, in the smoky chaos of New Delhi's overheated streets, small mobs of protesters gather, calling for Shourie's head.

Protests against Shourie are common, but the cause of the latest outrage is rattling India's fragile minority government. For the first time, the Indian Express, the country's most politically active newspaper, has turned openly against Prime Minister V.P. Singh, whom the paper helped bring to power.

"He is a person who does not have a national perspective," editor Shourie said in an interview. "He calculates as a petty, traditional 'party politician.' The vision of India as one -- that's missing in him."

Shourie's harsh words represent a dramatic turnabout from last year, when the Indian Express relentlessly trumpeted Singh as the only leader capable of rescuing the country from what Shourie called the corrupt and nepotistic reign of then-prime minister Rajiv Gandhi.

The source of the Indian Express's campaign against Singh -- which includes daily front-page editorials under Shourie's byline and calls for a mass movement against the prime minister -- lies in a volatile national debate over caste, job quotas and affirmative action. The debate has sparked violent student protests around India, leading to more than 50 deaths in the last several weeks, including a number of public suicides by upper-caste students.

In mid-August, Singh announced unexpectedly that he intended to fulfill a campaign pledge by setting aside half of all government jobs for applicants from India's lower castes and aboriginal tribes. The prime minister said the move was necessary to create opportunities for the hundreds of millions of Indians who have languished for centuries at the bottom of a rigid caste and social hierarchy.

Upper-caste university students have reacted emotionally, taking to the streets in poorly organized bands and attacking buses. The army has been called out in some areas to quiet the growing agitation. The students' main complaint has been economic -- they fear that with opportunities for upper-caste graduates slashed, they will face bleak job prospects. Singh's decision to set aside an additional 5 to 10 percent of government jobs for those in economic need has done little to quell student anger.

In speeches and frequent editorials, Shourie has framed the anti-government crusade in broader terms than the job quota issue. The protest movement, the editor says, must stand for "the affirmation of an identity of modernization in India, that these caste forces are being dissolved in our society and that Singh, for parochial and electoral reasons, is giving them a lease on life."

Shourie argues that job quotas on the basis of caste will exacerbate already deep social divisions, encourage mediocrity in India's moribund bureaucracy and retard economic development.

"I'm all for affirmative action to the extent society can afford it," Shourie says. "You say 'lower castes' are undernourished? Give them free lunches. You say they don't have a place to study? Give them free hostels. . . . But there cannot be any reverse discrimination in employment. At the start of the race, everybody must be equal."

Whether the national crisis over the continuing student protests will threaten Singh's position remains to be seen. Yesterday the prime minister survived a parliamentary confidence vote called by his own Janata Dal Party, winning a unanimous endorsement after a six-hour, closed-door debate.

Shourie's own role is ambiguous. An unassuming man who lives and works with armed bodyguards all around him, he describes himself as the only truly independent newspaper editor in the country, a modernist and a social liberal in the American tradition.

But some Indians see his newspaper as an unprincipled stalking horse for various political and business interests, and they attack the paper's sometimes partisan, sloppy and sensational reporting.

Shourie's adamant opposition to the Moslem separatist movement in Kashmir and his paper's close adherence to the Indian government's line on that controversial issue also have provoked charges that the Indian Express is merely a front for Hindu conservatives seeking to take power in New Delhi.

"I've grown deaf to these charges," Shourie responds. "Every day they burn my effigy. Earlier, Rajiv Gandhi's people did it. Now, it's V.P. Singh's people. That shows our objectivity."

Few in the Indian capital doubt that Shourie's power is genuine. Cabinet ministers drop by his office regularly for impromptu consultations. The targets of his crusades single him out for abuse. At one point early in 1989, Gandhi became so enraged by the Express's investigations into alleged government corruption that he shut down the newspaper and locked Shourie out of his office for 45 days.

An editorial cartoon from a rival newspaper hangs in a frame above Shourie's conference table. In it, one Indian politician laments to another, "The real issue is whether parliament is supreme -- or Arun Shourie."