NEW ORLEANS -- Time is supposed to move on, even down here in The Big Easy, and some day, inevitably, there is going to be a governor's race without Edwin W. Edwards in it, without a candidate who evokes the legacy of Huey Long and a form of easygoing populist sleaze known as the Louisiana Hayride.

Four years have passed since Edwards ran a campaign that was dubbed the last hayride. Didn't his ensuing corruption trial, which is remembered not so much for the verdict of not guilty as for the image of a governor paying off a huge gambling debt with a suitcase full of cash, finish him with the voters?

Not in Louisiana, where politics is theater and there is always demand for another encore. So it is that silver-haired Edwin Edwards, at age 60 still the fastest tongue in the South, is running for governor again, seeking his fourth term in an office he has held since 1971, with one four-year hiatus because of a constitutional restriction. As a campaigner, Edwards has enough bad-boy vinegar left to ensure the race's entertainment value, but his four opponents in Saturday's primary are naturally trying to make it something more definitive: a serious referendum on reform.

As the primary campaign enters its final act, Edwards is fighting to be one of the two candidates left on stage for the Nov. 21 runoff. While Edwards has been abandoned by the state's middle class, as indicated by polls that show him with about 8 percent of the white vote, he is depending on his strength among blacks and labor unionists to carry him through. The race is close enough -- the latest polls show him tied for that second spot -- that his political career could end this month, but few are really expecting it.

There is more uncertainty about which two opponents could knock him out among Democratic Reps. Charles E. (Buddy) Roemer III and W.J. (Billy) Tauzin, Republican Rep. Robert L. Livingston Jr. and Secretary of State Jim Brown. A poll for WDSU-TV here this week had Roemer in first place, with 23 percent; Edwards and Livingston tied at 18 percent, and the rest around 9 percent. Livingston, assured of the Republican base, and Tauzin, the favorite of Sen. John Breaux (D-La.) and the state's Democratic establishment, were considered the early favorites, but Tauzin now looks to be in trouble.

Roemer's surprising ascendance in recent weeks is reminiscent of the surge that carried Harry Hughes into the Maryland governor's mansion a decade ago following the corruption trial of Gov. Marvin Mandel. A Mr. Clean candidate like Hughes, Roemer trailed the field in money and name recognition until his state's major newspaper gave him a front-page endorsement. Rarely do such endorsements have much impact; the situation has to be just right. It was for The Baltimore Sun to propel Hughes in 1978, and it seems to be for The New Orleans Times-Picayune to help Roemer this time.

Roemer, 43, a fiscally conservative, culturally liberal representative from Shreveport, the major city in fundamentalist north Louisiana, is a gambler in his own right who plays poker in Washington with several journalists. But in other respects, his campaign is in direct contrast to that of Edwards.

Roemer has refused to accept cash, loans and contributions from political action committees. His major themes are to pay teachers more and education bureaucrats less, create an office of inspector general to root out state corruption, and force Louisiana's oil, gas and petrochemical industries to clean up what might be the most polluted state environment in the nation.

"I'm out to slay the dragon," says Roemer, presenting his case against Edwards and the Louisiana political tradition in fairy-tale terms.

Edwards, as the dragon, is playing his part in inimitable fashion. "I'm not a do-gooder like these other fellows," the governor said. "I play the game." The game is old-fashioned give and take. The state's unemployment rate might still be above 10 percent, and the state budget might be in the red, but when Edwards is on the campaign trail, the good times roll.

In the last two months, he has dished out nearly $11 million from an account in the state highway department that is known as his campaign-year slush fund; the project money always seems to go where his supporters are. The other day Edwards arrived in Natchitoches for the ribbon-cutting ceremony of a new stretch of Interstate 49 and put the issue in typical Edwards perspective with a bit of doggerel:

I know you've had a long, long wait

To see the opening of this interstate.

I'll need your help in about 10 days

Remember . . . Edwin Edwards built these highways!

Edwards, who spent nearly $20 million four years ago in his successful effort to unseat Republican Gov. David Treen, has raised less than one-quarter of that this time around, most of it in large contributions from corporations that do business with the state. Roemer's staff likes to refer to Edwards' fund-raising maneuvers as "The Louisiana Purchase, Part II," but in fact times are so tough that no one is getting much money. The candidates are spending most of their funds on television, except for Edwards, who is saving $800,000 to $1 million for Election Day walk-around money for his precinct workers.

Paying for endorsements is a tradition in Louisiana, and Edwards has spent thousands of dollars lining up support in the black community, where he is expecting 80 percent of the vote. Seeking black support has been more difficult for the other candidates, who are caught between their desire to have a racial coalition and their political imperative not to do business the way Edwards does.

This has proved especially touchy for Tauzin, a Cajun who began his career as one of Edwards' floor leaders in the state legislature but who now says Edwards "betrayed his promise to the people of our state." Tauzin, known in Washington as an effective compromiser, has found that quality of little use in this race; in fact, he has been caught between the images of Edwards and Roemer, sometimes seeming uncertain about which way to go. He was hurt last month when his campaign reports showed a $10,000 payment to three black councilmen in Shreveport for what were listed as "endorsements."

Tauzin's predicament was also in evidence as he sought the endorsement of Breaux, his old Louisiana State University Law Center classmate and best friend. Breaux, who began his political career as Edwards' congressional aide, was for months reluctant to choose publicly between the two men. He said the decision was so difficult that he would do anything to avoid making it. "I'm thinking of having a heart attack," Breaux said at one point. "Not a big one, just a mild one."

Last week, with Tauzin slipping in the polls, Breaux finally endorsed him, an action that prompted ridicule from Edwards, who said: "There's still one seat left on the Titanic."

For Livingston, an earnest, methodical Republican much in the mold of Treen, who lost to Edwards in 1983, and W. Henson Moore, defeated by Breaux in the 1986 Senate race, the aftereffects of those two races are still being felt. Moore's quick demise last year, after a race in which he was for months the front-runner, seems to have especially damaged Livingston because it led some voters to conclude that the Republicans simply could not win in Louisiana. Many of Moore's volunteers in Baton Rouge are working for Roemer.

While Livingston can claim that he is the cleanest break from the Edwards era, he also presents the starkest contrast in terms of rhetorical eloquence. Edwards, Tauzin and Roemer, and to a lesser extent Brown, are quick thinkers and orators, but Livingston is plodding. At the candidates' first debate, he completely lost his train of thought while answering a question, and after a painful silence had to mutter a bewildered "I pass" into the microphone.

Edwards, however, has never been caught without something to say. The closest he has come to that during this campaign was at a recent debate when a reporter asked the candidates whether anything in their pasts that had not been revealed might show a character flaw. After a moment of reflection, Edwards, an acknowledged craps player and womanizer, responded: "I guess the sad truth is that everything good, bad or ugly about me has already come out. I've had enough public sins, and I'm sorry but I just don't have any more."