"They giggled, they gasped, they held their breaths, and the show went on."

Thus did historian Harnett T. Kane record the mindset of the people of the "Gret Stet of Loosiana" half a century ago, when Huey Pierce Long, the legendary "Kingfish," emerged as governor from the muck and misery of the Depression to build a political dynasty as gaudy and grand, as rotten and flavorful, as any the state or nation has seen.

The Long era, dubbed the "Louisiana Hayride" by Kane, came crashing to a close last week. Its passing is being treated here with civic sobriety -- uncharacteristic and of a kind that Louisianians, since well before the Longs, have been hellbent on avoiding.

Death came, rat-a-tat, in two blows.

Last Monday, Huey Long's son and only political blood heir, Democratic Sen. Russell B. Long, 66, unexpectedly announced that he plans to retire in 1986 after 38 years in Congress.

Three days later, the Kingfish's spiritual and stylistic heir, swashbuckling three-term Democratic Gov. Edwin W. Edwards, 57, was indicted by a federal grand jury on charges that he used political clout to pocket $2 million for himself and another $1 million for his brother on hospital construction deals from 1982 to 1984.

Both events followed by only two months the death of Rep. Gillis W. Long, Russell's distant cousin, who was just starting his eighth term in Congress.

"It's as if the whole state is unraveling," independent pollster Ed Renwick said. "First Gillis Long, then Russell retires, now Edwin is indicted. We're a state that likes our leaders outsized. It will take time to adjust."

The adjustment must include dealing with unfamiliar new jitters about the state's image and respectability. Louisiana is running out of oil and gas, and its leaders sorely want to diversify the economic base. They have begun to fret that Louisiana's long love affair with political scoundrels has become a dangerous indulgence that might keep new industry away.

"I suspect we're in for an age of less flamboyance and fewer shenanigans," said John Maginnis, a biographer of Edwards.

But what a run they had here.

The Long era paraded a gaudy assortment of populist demagogues before a public adoring and cynical. It elevated chicanery and bossism to high art even as it literally lifted the state out of mud and ignorance with a massive program of highway, bridge and university construction.

And it spawned Huey Long's incipient presidential campaign, which was stopped by an assassin's bullet and whose "Every Man a King" and "Share Our Wealth" slogans amounted to what one chronicler of the day called "hillbilly Marxism."

Perhaps even more memorable was the riveting human drama at every turn:

* The assassination, 50 years ago this September, inside the 34-story state capitol tower he had built in Baton Rouge as his own civic citadel, of the 42-year-old Kingfish, then a U.S. senator at the height of his popularity.

* The involuntary institutionalization in 1959 of the Kingfish's younger brother, Gov. Earl K. Long, who, after fulminating incoherently for hours one evening on the floor of the state Senate, was whisked away by friends. Placed under heavy sedation, he was flown to a mental hospital in Galveston, Tex. A week later he talked his way out and returned to the governor's mansion in Baton Rouge to fire his state hospital commissioner in order to keep from being recommitted.The grand jury indictment this week of a governor who has made a career of daring trouble and skating away. The indictment was Edwards' first, but the grand jury was at least the 10th that has investigated him.

In Louisiana, it has been said that a politician's first obligation is to entertain, his second not to get caught stealing and his third to govern.

The state was settled not by dour Puritans, who slipped easily into a town-meeting format of democracy, but by French and Spanish colonial governors, whose royal notions of governance included kickbacks, nepotism and patronage. Even they plundered with style.

So did the Kingfish. Although the state legislature once tried to impeach him, he was enormously popular with the citizenry. Before he was slain, he had begun laying groundwork for a 1936 challenge to President Franklin D. Roosevelt on a platform that called for the federal government to give all citizens a homestead, an old-age pension, and perhaps even a refrigerator and radio.

The Kingfish was never caught with his hand in the cookie jar, although he ruled by a "deduct" system wherein each state employe tithed 10 percent to the Long political organization.

His successor, Gov. Richard Leche, was jailed in 1940 in a huge state road-building scandal.

"It's an occupational hazard," Leche philosophized on the way to the hoosegow. Earlier, he had noted, "When I took the oath of office, I didn't take any vows of poverty."

Before the scandal subsided there were 250 other indictments that resulted in six suicides and scores of convictions, including that of the president of Louisiana State University. The Long Machine survived the scandals of the late 1930s, but it never fully recovered.

Huey had grown popular because he was a poor, Bible-quoting farmboy who could stand up to the oil and gas bullies and the Yankee traders who had been dominant in the state. His son, Russell, elected to the Senate one day before he turned 30, was never the same sort of radical populist.

"He wanted to tax it away from those who had it," Russell once said of his father. "I wouldn't keep anybody rich from getting richer."

Over the years, Russell grew cozy with oil and gas interests. On racial matters, however, he hewed to the family heritage and was considered enlightened for a white southern politician of his era.

Russell's chief failing, viewed from here, was a bland and inscrutable personality.

For a while, alcoholism and his marital spats fed his constituents' appetite for scandal, but he righted himself, became an expert at the arcana of the tax code and eventually a full-blooded creature of Washington.

"He is a toned-down, atypical King," journalist A.J. Liebling wrote of Russell Long in 1960. "The equivalent of a Samson with a store haircut."

For flair, Louisianians of the current generation have relied on Edwards, the irreverent, charming, perpetually tanned Cajun who never misses a chance to advertise his taste for dice, women and chicanery.

Once, when one grand jury or another was on his tail, he was asked at a news conference if he worried that the governor's mansion might be bugged. "I can't image who would want to," Edwards shot back, "except maybe some jealous husbands."

Edwards kept on wisecracking right through his indictment, greeting the cameras while clad in an orange and purple LSU jogging suit.

He may well be the nation's only governor who claims that his real ambition is to be a television game-show host.

Many Louisianians rallied to Edwards' side late last week, and many say they believe that he will be acquitted.

As Edwards, reelected in 1983 by a 2-to-1 landslide, noted: "Any jury in this state is bound to have eight Edwards supporters."

But Edwards is not the state's only folk hero of the moment. There is plenty of support for U.S. Attorney John Volz, the flinty, crusading, Democratic-turned-Republican prosecutor who has put mob figures and some of Edwards' high-ranking appointees behind bars and is now going after the governor, who would be the biggest catch of his career.

Biographer Maginnis said he was lecturing student government leaders from around the state when Edwards' indictment was announced last Thursday. He gave them the news of the governor's travails.

They did not giggle, Maginnis reported. They did not gasp. They did not hold their breath.

They applauded.