Dr. Julio Cesar Barreto Fonseca, at 92 an aging lion of Leon, remembers the day he watched U.S. forces occupy his city in 1926. "The Marines came up on the train from Corinto, about 5,000 of them," he recalled. "They formed up there at the station and marched toward town. The Nicaraguan forces were drawn up on a line, awaiting them."

Barreto's house, typical of Nicaragua's second largest, most historic -- and surely hottest -- city, has a red-tile roof that pitches out over the sidewalk, providing some shade in which a man can reminisce.

The aged surgeon's eyes are dimming and he says he reads too little to comment on the current U.S.-sponsored intervention in his country. Such detachment is rare in this one-time colonial capital. The threat that the Marines might return dominates life in Leon, known as the cradle and indeed the capital of the 1979 revolution.

The Marines were first dispatched to Nicaragua in 1909 and then repeatedly over the next two decades. Initially they were sent to secure a canal route that was then favored over the Panama route eventually chosen by President Theodore Roosevelt. Later they became the arbiters of local politics, manipulated by those who held power and despised by those who didn't.

Americans may have forgotten that history, if they ever learned it. But to Nicaraguan nationalists, the memory of American intervention is a dominant factor in their conflict with the Reagan administration. The ideology of the Sandinista government, and more particularly its performance, are divisive issues here -- many from the city have chosen exile, and others hope to leave. But probably a majority of those remaining are accepting of the revolution, for all its problems. And the U.S. trade embargo or increased aid to the contras seems to only rally support for the government the White Houses seeks to weaken.

Bombed-out buildings, including several of the city's 23 Catholic churches, are jagged reminders that the Sandinista revolution made Leon, not Managua, its headquarters. History shows that Leon, though apt to shift loyalties on occasion, is a rebellious place, and above all a city of fighters.

But the 1926 intervention, Barreto asserted, was a peaceful one. "And do you know why? The Nicaraguan general spoke English, and he went out and talked to the Marines. They came to an understanding. A few drunks took a couple of potshots as the Marines marched into town, but there was no other trouble."

The Sandinista leadership of Leon is determined the Marines will not return, and if they do, it will not be peaceful. Gladys Baez, a Leonian peasant whose exploits won her the title of guerrilla commander, said 1,593 residents of the region embracing Leon were killed last year fighting the U.S.-backed counterrevolutionaries.

"I want American mothers to know," she said, "that their sons who come here will never leave alive."

The city certainly is burying its own sons, shipped home from the fighting zone 50 miles away. The mothers despair of ever completing their Museum for the Martyrs of the Revolution. The honor list is growing faster than they can find the requisite photos to hang on the wall, and anyway they are running out of space.

But it may be that Baez, a ranking member of the ruling party, offered an inflated casualty figure. Seven years after the overthrow of dictator Anastasio Somoza, statistics -- like car parts and canned goods -- are hard to come by, and often unreliable when found. It is known, for instance, that the population of the Leon areawas about 150,000 before the revolution; what it is today is harder to know. The region's top official acknowledges a massive rush to exile of the elite that once found comfort in this city. Many of the poor have fled as well, particularly those of draft age. Perhaps 40,000 have departed, certainly including the backbone of what might have been an active opposition here today.

Not that those remaining are blindly loyal. A visitor finds no shortage of critics, and the complaints -- as Baez and Marta Crenshaw, the Sandinista governor for Leon and an adjoining province, acknowledge -- can be as withering as the sun. "These are a people with no hair on their tongues," said Crenshaw, who is a naturalized Leonian, having only 13 years here.

Crenshaw, Baez and their supporters attribute each shortage to the U.S. trade embargo, each authoritarian action to the exigencies of the contra war. And they also point out that no antigovernment sabotage has occurred in Leon -- a fact even the most determined contra supporters acknowledge.

"We lack leadership," said a young draft dodger so anti-Sandinista he said he would like the Marines to return.

But this city is a poet as well as a fighter. Its impressive cathedral, though a bit shabby now, is worthy of the colonial capital Leon once was. These days, in the words of a dowager benefactor, Maria Lacayo Teran, "it is too much cathedral for a small city."

Leonians love to describe how, in the Spanish epoch, word went out from Madrid that two cathedrals must be built. One was to be in Lima, Peru, the New World's one grand metropolis. The other was to be here in Leon, a tropical town of modest pretension. But in the ocean crossing, so the story goes, the plans got switched.

The bones of Ruben Dario, a native son who became one of the two or three great Latin American poets, are buried in a crypt guarded by a marble lion. Dario died of drink in 1916 after having watched with bemusement the bloodthirsty politics of the time, including the first Marine incursions in his country.

Dario wrote of his first years in an exquisitely simple house here, now a museum: "The men of politics came and talked of revolutions. Dario's aunt rocked me in her lap. The conversation and the night closed my eyes."

He led the high life from Buenos Aires to Madrid, but described his audience as "the ingenuous America, which has Indian blood, which still prays to Jesus Christ and still speaks Spanish," and not the other America "of men with Anglo-Saxon eyes and barbaric souls." He died in Leon, the one major Nicaraguan city with a continuing Indian influence.

Befitting a colonial capital, Leon has its institutions drawn up around the plaza. The cathedral still dominates, but the church is on the defensive. It is the sole institution with mass appeal here that is resisting the Sandinistas. Sunday masses draw crowds of all ages, and even on weekdays, teen-agers enter the cool of the sanctuary to pray before a lifelike depiction of Christ in the tomb.

Tension between church and state began long before the Sandinista revolution, as the church reluctantly relinquished its once preeminent powers. Now the process has accelerated.

The Rev. Msgr. Marcelino Areas, the cathedral's 75-year-old curator, reached back in history to insult his adversaries. "Sandino was a thief," he said, referring to Augusto Cesar Sandino, the nemesis of the Marines in the early years of this century and the namesake of the movement that has given birth to the hemisphere's latest experiment in Marxism.

The monsignor stepped aside for a passing column of third-graders in blue and white uniforms. "The great majority of Leon's youngsters still attend Catholic schools," he said. "But we must teach them the state curriculum. That is checked very carefully. Still, the poorest pay their tuition to attend." State officials contend that 60 percent of youngsters now attend public schools.

In the old days, the university was Catholic, too, attracting the scholars -- and the poets -- of all Central America. It survives on the corner of the plaza as the Seminary of San Ramon Nonato, 306 years old but now a training school for fewer than 24 priests. The state university that began displacing it in 1947 now has 5,000 students, quadrupling since the revolution. Faculty members acknowledge that the quality of education has fallen accordingly, but they have high hopes. The schools are scattered around the city, with the main building peeking into the plaza from the corner opposite the seminary.

San Ramon's rector, the Rev. Sergio Soler, is 30 years old. "It is the same as in the government, where the very young must also take positions of importance," he said. He described the shortage of priests as acute, compounded by the general exodus.

Nationally, the conservative stance of the Catholic hierarchy has provoked a young minority of priests to form a "revolutionary church," led by suspended priests with posts in the Sandinista cabinet. Soler said that in Leon, "they are only a few, and they have no force." Some Maryknoll sisters seem to be the major exception.

Leon's bishop, the Rev. Msgr. Julian Barni, an Italian, caused a stir recently with his comment on the U.S. congressional debate on funds for the contras: "While in the United States they are discussing the $100 million, the Soviet Union has already given $100 million and much more without any discussion at all." He called for "both imperialist powers, not one alone," to quit complicating matters in Nicaragua.

Soler said there is "no open prosecution of the church here, but a few incidents, some of them grave, convince us that the Sandinistas have ideological plans to destroy the church in the long run."

Both he and his bishop point out that the church supported the overthrow of Somoza, and Soler insisted that this diocese, in particular, remains open to dialogue. He noted that when Jimmy Carter visited Nicaragua earlier this year, President Daniel Ortega brought him to meet Barni.

The sweeping nature of the revolution that brought the Sandinistas to power is epitomized on the plaza by the transformation of the Social Club, where the elite used to meet, into a government-operated Youth Club. The country club, too, was taken over, and the city has only one restaurant to which a customer would willingly return. There is no clientele even were the makings of a menu available. Youngsters dance to American rock music at the ex-Social Club, where cotton farmers used to entertain.

It was at the Social Club, in 1956, that the first of the Somoza clan, Anastasio Somoza Garcia, was assassinated.

The Somozas were not from Leon. The killer, Rigoberto Lopez Perez, a Leonian, was quickly caught and killed. He is now a national hero, with a floral monument to him facing the plaza. Barreto, the 92-year-old, embarrassed the daughter with whom he shares the shade of his doorstep by declaring that Lopez was one of his three-score illegitimate sons.

"I had known Somoza, and had a drink with him that morning," said Barreto. Somoza's son and eventual successor never acknowledged the doctor's relationship with his father's assassin, according to Barreto, but he "knew very well and began to take away my properties."

The younger Somoza had served his apprenticeship in government here after graduation from West Point. A Leonian now in exile remembers him "wearing black and white boots, riding a Harley-Davidson." He made a favorable first impression -- another old-timer watched him reeling out the first phone line to connect Leon with the outside world -- but soon moved on to Managua.

While the Somozas had largely appropriated the Liberal Party, whose base was Leon, the city and the first family developed a mutual antipathy that no doubt encouraged Leon eventually to take the lead in bringing down the dynasty. But for the people of Leon the conflict was not without cost.

Up until World War II Leon remained Nicaragua's principal city. But when the war put the security of the Panama Canal in jeopardy, intervention by the United States -- though not with the Marines -- once again shaped Leon's future. U.S. engineers revived the dormant Pan-American Highway project, and in the rush down the isthmus, the route worked out with the elder Somoza bypassed Leon. The transportation link assured Managua's ascendancy and prompted a surge of growth that paused only in the aftermath of the 1972 earthquake.

The one statue in Leon's plaza, oddly enough, is of liberal politician Maximo Jerez, who was a cause of the city's losing the capital in 1857. To his everlasting shame, he had invited an American, William Walker, to Nicaragua two years earlier to help make war on the conservatives of the rival city of Granada.

Walker was a precursor of on the conservatives of the rival city of Granada.

Walker was a precursor of the Marines, in his way, landing with 58 adventurers and soon seizing the presidency. His goal may have been to add Nicaragua to the pre-Civil War union as a slave state. In the accompanying uproar, Leon was defrocked as capital in favor of the compromise town of Managua, roughly halfway to Granada.

Walker, who by all accounts feared very little, apparently sensed the cold stare of Leon and spent his time making trouble elsewhere in Nicaragua. A U.S.-engineered peace eventually extricated him, but he ended up before a firing squad in Honduras.

Jerez spent the rest of his life atoning for his indiscretion, at one point offering himself as a target for a hidden sniper then threatening the city, so soldiers could spot the source of the gunfire. The sniper shot Jerez in the leg, but the soldiers got their terrorist and Leon had a hero worthy of the plaza.

Leonians tend to think of events important to them as surely having taken place in the plaza. Especially it is considered the venue of plotters. One of the ex-players in the city's turbulent brand of politics offered this image: "When the cathedral bell rings at 8, calling the people to prayer, some Leonian is sitting on a bench thinking, 'What should I be up to next?' "

But while the Sandinistas arguably have lost control of the economy, their control of the plaza seems firmer. The takeover of the Social Club was followed by that of the bookstore, which offers Cuban editions of Marx, Lenin and even an occasional Engels, in hard back or paper, but very little else.

Most days, a few U.S. or European volunteer workers will be sitting at a table of the plaza's open-air snack bar, looking dazed by the heat and thanking the waitress excessively for a cold beer.

A Briton trying to learn Spanish had found a copy, not at the bookstore, of the favored introduction to the new Nicaragua, Commander Omar Cabezas' "The Mountains Are Something More Than a Huge Green Steppe." Cabezas, as near as Leon has come to producing a poet of the guerrilla revolution, offers this description of his home town at Easter time:

"It's so hot that you'll see the dogs coming along the inside of the sidewalk, where the people are walking precisely because there is a little shade. And that shade is hot, too, . . . (I want to persuade the reader . . . that Leon is hot. That this isn't my invention. That it's hot.")

The paucity of poets in current-day Leon is as unaccountable as was their abundance in the past. Barreto, who wrote verse when he was not in surgery, named half a dozen poets who were with him at the university. One of them, Alfonso Cortes, became the city's second most famous, after Dario. By all accounts, he ended up mad; Barreto said his muse was booze. Perhaps it was that he lived in the same house as had Dario.

Across the aisle of the cathedral from Dario's tomb are words of Cortes, lettered in gothic on a marble plaque and fairly ringing in their spare Spanish. Surely no other house of worship provides such a temporal poem for its congregation to ponder:

The Great Prayer

The dream is a solitary rock on which the eagle of the soul nests.

Dream. Dream, during life's daily routine . . .

Oh! those dead who never have lived,

Oh! those living who will never die . . .

Cortes did die, in 1969, after terrorizing a generation of young Leonians. In his declining years, he roamed the plaza, strapped in a straitjacket, hurling bolts of sonorous words.

Neither the plaza nor the the city has really taken on a military air, despite the Sandinistas' military leanings and predilection for uniforms. Patrols carrying automatic weapons do make occasional rounds, and workers in Leon's regional, local and even neighborhood offices of the ruling Sandinista Front effect some form of olive drab.

Aside from the snack bar, the last stands of private enterprise in the plaza are those of the wizened shoe-shiners. They are the nearest thing, as well, to a local newspaper since the daily Centro Americano closed several years ago. But if the talk there beneath the trees has turned to rebellion of late, the bootblacks are keeping it to themselves.

Private business still exists in Leon, if not on the square, but its defenses seem weaker than those of the church. Its redoubts are the chamber of commerce and the cotton growers' organization, the Association of Farm Producers headed by Jose' Pallais.

The economy of this region began developing a dependency on cotton after World War II as farmers adapted antiparasite technology developed by an American farmer in El Salvador. The lowlands around Leon proved capable of producing a high-quality fiber abundantly. But Pallais makes a compelling case, corroborated in large measure by available statistics, that the Sandinistas are throttling cotton by driving out efficient producers.

"In this country, political conquests are more important than raising the economic level of the people," said Pallais. He said his organization represented 230 producers in 1979, but only 153 are still on the land today.

The farming of big cotton is a demanding business, needing capital for fertilizers, insecticides and equipment. With each season, they become harder to obtain. Pallais said farmers must now factor in black-market prices for goods unavailable otherwise. They work on the assumption that inflation will be 300 percent this year.

Unlike the cab drivers and housewives, the cotton farmers are little persuaded by the official argument that the U.S. trade embargo is responsible for the shortages. Farmers see a shortfall of foreign-exchange earnings that limits purchases, from whatever source except perhaps the Soviet Union, of the imports on which Nicaragua is utterly dependent.

Pallais said cotton production has fallen each year at an accelerating rate, as the percentage of land under state or cooperative tilling has caught up with and surpassed the private holdings. Pallais' pessimism was all the more compelling, given that he is one of the nationalists who have chosen to stay.

As with all revolutions, a major question is whether the beneficiaries of the change have gained enough to offset the losses of those who now are relatively put upon. As Crenshaw, the central government's chief executive in Leon, said: "It is difficult now for one who has lived well to continue in this poverty. We do live poorly. But there are some valiant intellectuals and professionals who are living worse and staying." The problem is that there are not many of those.

Innkeeper Victor Manuel Caldero'n can match the most mordant critic of the revolutionaries with his accounts of official ineptitude. But on balance, he said, "the outcome is heavily for the good." He cited the Sandinistas' massive efforts to offer the peasants reading, writing and tractors -- "even if they are Russian tractors," as a neighbor put it.

Caldero'n's little Hotel Europa is on a road that farmers take into town. Not much passes that he fails to note. "Since independence, we have never had a government that was genuinely popular. The Sandinistas are popular with those who had nothing," he said.

"Under this government, the workers are beginning to change . . . In my 74 years I never expected to see a government that sought to give land to the peasants. I never thought I would see those peasants drive by here on a tractor."

Unlike Barreto, Caldero'n seemed reluctant to revive his obviously bitter memories of when he was 14 and watched the Marines pull up just across the way at the station. He did tell this story, though:

"Then as now, over there at the market, the women selling their goods sometimes got into fights. There could be some terrible rows. To keep the peace, the city appointed a judge of the market. He would listen to both sides and he'd settle the argument then and there."

What happened next would seem to be a metaphpor for those who say the United States cannot get involved in Latin America without becoming snared in a morass.

"When the Marines occupied Leon," recalled Caldero'n, "they eventually got to the point that they even had to name the judge of the market."

While Leonians' attitudes cannot be gauged by posing a choice of Marines versus Sandinistas, the U.S. congressional consideration of $100 million in aid to the contras ended up providing some measure, however rough.

Government newspapers, which circulate far more widely than the opposition La Prensa in Leon, followed the debate in Washington so intensely that this reader, anyway, could only wonder if the Sandinistas secretly hoped the aid bill would pass.

The specter that the $100 million invokes -- that of the foreign threat, the lion at the gates -- clearly has credibility in Leon. When the Agricultural Workers' Union a few blocks from the plaza decided to salute a young heroine of the early efforts against Somoza, it posted a notice on the bulletin board beginning:

"Not even with the $100 million will the imperialist aggressors be able to crush this revolution that the workers and peasants are defending."

Governor Crenshaw got word from Managua to mount a massive demonstration on the day, in mid-April, when the House vote on the $100 million was expected. But there was some uncertainty about the timing of the vote, so the rally was called for the ostensible purpose of remembering six Leonians slain in the '79 revolution. Crenshaw predicted a turnout of 30,000.

A sound truck made its way, loud and slow, through the streets. The party's minions at the block level and in the offices issued their calls to report to the plaza at 3:30. That hour passed with the taped music from the truck echoing around the plaza. An undulating file or two from union halls arrived, and an arm-banned party member, passing out balloons, explained that Leonians are always late.

A crowd eventually gathered, paraded out to the memorial for the six slain on the edge of town, and listened to the denunciations of the $100 million aid bill. The vote, it turned out, was postponed.

Partisan estimates put the crowd at more than 30,000. A Dutch backpacker, apparently inexperienced at judging crowds, exalted that there must have been 1,500. Caldero'n, the innkeeper, pronounced the turnout 15,000 and seemed content with that.

"I think this revolution could succeed," he said, "if only we could bring back the boys in the army and put them to work here."