"LAISSEZ LES bon temps rouler!" he proclaimed as he spent $20 million to win his third term as governor of Louisiana four years ago -- let the good times roll. But the times have not been good, and after Saturday's election Edwin Edwards was singing a different chanson. Louisiana has spent much of the four years of Mr. Edwards's latest term suffering from the nation's highest unemployment rate, and the governor has spent much of those four years defending himself in court against charges of corruption.

Mr. Edwards won his legal fight, getting a hung jury in his first trial and an acquittal in the second. But the political battle was beyond even his considerable powers to win. In Saturday's primary he trailed Rep. Buddy Roemer by a 31 to 28 percent margin. The governor's only base of support was among the state's black voters; Mr. Roemer won large margins in Protestant northern Louisiana and ran almost even among Republicans with the one Republican in the race, Rep. Bob Livingston. It helped that Mr. Livingston lost track of his thought in one debate and that Mr. Roemer's voting record in the House has been close to those of Republicans. Reading the returns in the Hotel Monteleone in the French Quarter Saturday night, Edwin Edwards could see that he had no prospects for increasing his vote in the runoff. He went down to the ballroom with his wife (whom he once appointed to fill a vacancy in the U.S. Senate) and with characteristic aplomb announced that he was quitting the race. So Buddy Roemer is the next governor of Louisiana.

What kind of governor he will be? He seems unlikely to exert the command over the state's public life that Edwin Edwards and Huey Long did in their times. Probably most Louisianans hope he can get down to the less dramatic, but now urgent business of building up the state's economy and elevating -- there is plenty of room for this -- the tone of its public life.