Flapping desolately in the hot, dusty breeze, a cardboard sign hastily scrawled in flowing Urdu script summed up the impetus behind the violent drive to force Prime Minister Zulfiqar Ali Bhutto from power:

"Learn the Lesson of Indira Gandhi."

The lesson is that the former Indian prime minister, confident of mass support after 21 months of authoritarian rule, called national elections and was voted out of office overwhelmingly.

Inspired by the example of democracy set by their giant neighbor and traditional enemy, Pakistanis are demanding the same from Bhutto. In growing numbers they charge that the elections Bhutto held March 7 were massively rigged, enabling him to claim 155 seats in a national assembly of 200.

"The Indian example," a phrase heard throughout this embattled industrial and port city, has been a key in expanding what would probably have been a simple political protest into a mass movement.

This movement now presents the greatest threat to the political and economic stability of Pakistan since the disgrace of the military defeat in Bangladesh in 1971, in which the former east wing of Pakistan won its independence.

The demands for genuine democracy, for Bhutto to resign and for new national elections, have passed swiftly from Bhutto's political foes to the citizenry. For the first time in Pakistan's 30-year existence, it is not just the poor with nothing to lose who are making the demands. Lawyers, journalists, wealthy businessmen, professionals, academics and students have joined them.

It is the poor who are taking to the streets of Karachi, Lahore and Hyderabad, where military law was declared two days ago, and other cities where continuous curfews have been imposed. It is the poor who are being shot by the army and the police. Reliable estimates put the dead at nearly 400 and the injured in the thousands, with fresh counts daily.

The more privileged classes protest among themselves behind the guarded walls of their homes. But not entirely there.

In the Punjab provincial capital Lahore, the nation's intellectual hub and a key to Bhutto's fate, lawyers have organized and marched with black flags through the tree-shaded avenues and malls.

Journalists, cowed by steadily tightened restrictions during Bhutto's five years in power, have begun to express themselves in tentative but open editorials Newspapers that a few weeks ago kept opposition stories from their pages had begun printing anti-Bhutto demands and photographs of violence. Today, however, the government imposed censorship on all articles, photographs, cartoons and drawings related to the drive against Bhutto.

This will insure that foreign news reports - particularly from the BBC in English and Urdued will remain the main source of information. Foreign journalists covering demonstrations are immediately swamped by frenzied crowds shouting "BBC zindabad, BBC zindabad," meaning "Long live BBC."

As in India during the "emergency" period, harsh limits on the press not only cut off the flow of balanced news but also isolated the prime minister from the aspirations and frustrations of the people.

Although the energetic, 49-year-old Bhutto traveled frequently throughout Pakistan, neither he nor his intelligence network was able to feel the national pulse.

"We're not fools, you know," the British-educated wife of a major industrialist said last night. "None of us would be foolish enough to tell Mr. Bhutto or his wife what we were really thinking, but rather what they wanted to hear."

When the election campaign began, according to an activist Karachi attorney, Bhutto was "appalled and astounded" to find that his intelligence reports had been so far off. "On a helicopter flight over Lahore he couldn't believe his eyes when he saw the size of an opposition rally, the attorney recalled.

A retired army general, a personal friend of Bhutto's said that a few days after the voting the prime minister suffered "a near nervous breakdown and was put under sedation for several weeks." He subsequently dismissed about a hundred intelligence agents.

Gandhi, with a larger and more effective intelligence network, suffered a similar shock. Apparently she had no idea of the deep bitterness over the actions of her son, Sanjay. Bhutto, according to a number of Pakistanis who move in his social circle, had not realized how angry businessmen and other members of the elite were over governmental corruption - which he had condoned, if not becoming personally involved in it.

"It had reached the point where if one wanted a license, a permit, whatever," a Karachi industrialist said, "one would have to arrange a liaison between one's wife or mistress with this minister or that secretary. Financial payoffs, of course, were legion."

Bhutto also built an enormous account of personal hate among those politicians who are now attempting to drive him out. Virtually every important political opponent has a story of being beaten or tortured or sexually abused, his home or business burned or ransacked, or his wife or daughter raped during periods of arrest and interrogation.

"Now all these chickens are coming home to roose," commented the editor of a once-respected and now-banned magazine.

Although Gandhi jailed thousands of her political opponents, even her dictatorship reflected some of the influence of her father, the erudite and gentlemen Jawaharlal Nehru, and of the ascetic Mohandas Gandhi, of whom she hadbeen a disciple as a child.

Bhutto, despite the veneer of a British and American education, has deep roots in his base as a powerful landlord and feudal baron. In interviews with this correspondent, he regularly dismissed his opponents as "idiots" and the country's Islamic religious leaders as "the beards."

It was not just "the Indian example," but also the example Bhutto set for his people that accounted for his crisis. When he came to power after the collapse of East Pakistan, he seemed a different man. He swiftly pulled the country up by its bootstraps and within three years made it a showcase of progress.

His reputation at home and abroad soared. He established close friendships and an open line of credit, with the Middle East's oil states and put the economy on a sounder footing than when burdened by the poverty of East Pakistan.

Then he began making promises. He promised to nationalize industries. When he did it, production dropped and he began to de-nationalize. He promised to clear the national and provincial administrations of corruption. But corruption increased.

His promise of democracy, more than any other, he failed to keep. Unlike India, Pakistan had never been a democracy; but with the civilian Bhutto at the helm and the army in shame after Bangladesh, Pakistanis hoped its time had come.

Instead, they wound that Bhutto was as much an autocrat, as his military predecessors, Ayub Khan and Yahya Khan. Their hopes were crushed in last month's elections.