Jilted by an-American traveling public whose vacation fancies have turned to Mickey Mouse, Europe and a covey of Caribbean islands, this once-grand resort is eyeing casino gambling as a possible partner in a new life.

Two concerted campaigns to bring casinos to Miami Beach have been launched and even their formidable opponents admit it is gambling's strongest bid yet.

Introduction of casino gambling, its backers say, would change Miami Beach's image from that of a fading queen of tourism to a revitalized, swinging city. It would attract investors to renovate old hotels and build new ones. No new hotel has been built in Miami Beach in 10 years.

But opponents of the casinos say they would attract criminals, under-mine South Florida society and, besides, would not solve Miami Beach's problems.

Favoring the legalization of casinos are a number of prominent Miamians, including Miami Beach Mayor Harold Rosen, hotel operators Ben Novack of the Fontainebleau and Irv Cowan of the Diplomat, and National Airlines president L. B. Maytag.

Eastern Air Lines president Frank Borman, who like Maytag has seen his business weaken as Miami Beach's fortunes declined has recommended "at least a study of the impact of legalized gambling on the beach."

Opposing the move are Gov. Reubin Askew, the Greater Miami Crime Commission, most law enforcement officials, the powerful Greater Miami Chamber of Commerce and most of the media, including the dominant Miami Herald.

And as the debate gets hotter, both the proponents and opponents are keeping an eye on Atlantic City, N.J., another jilted lady of tourism which has joined hands with gambling.

Crucial to the pro-casino arguments is the shaky condition of Miami Beach after the steadily degenerating tourist count of the past decade. The past summer season has been particularly disappointing. The renowned Fontainebleau, for instance, took in only $436,000 in June compared to $1.1 million a year earlier.

"All of our data shows quite concisely that the beach is dying as a tourist attraction." Eastern's Borman said when he announced earlier this summer that his airline would seek new routes in the Caribbean, Central and South America.

"Miami Beach is a disaster," says state Rep. Charles Papy, who with colleague Paul Steinberg has filed a bill to amend the state constitution to permit casino gambling on Miami Beach. "You can rent the finest office space in Miami Beach for less than 50 per cent of what is charged in Miami or Coral Gables. Lincoln Road, the main shopping area, used to be one of the fashion centers of the world. Now it has vacant stores. Something has to be done."

The something Papy and Steinberg want done is the introduction of state-owned and state-operated casinos - two free-standing ones plus additional casinos in hotels with 450 rooms or more. They would be open only at night and would be the only place where non parimutuel gambling would be allowed. No lot machines would be allowed in drug stores or hotel lobbies. Except for the part about the state being directly involved, the plan is not dissimilar from Atlantic City's.

"I see gambling as the catalyst to get private investment back into the community," said Steinberg. He cited the $300 million that has been poured into Atlantic City since casino gambling won approval there.

Another approach to legalized gambling is being taken by a businessmen's group headed by Jay Kashuk. It is gathering signatures for a petition to force the casino question onto a state-wide referendum, and Kashuk claims to have 70,000 of the required 250,000 already. To get the remainder he plans to send a Winnebago-housed "casino caravan" touring the state.

The likelihood of gambling pumping new life into a sick Miami Beach was supported recently by a University of Miami finance professor who made a study of gambling's potential for the economic society of South Florida. Manfred Ledford said that casino gambling could easily double the total number of tourists here, but he also felt that Miami Beach should try to develop a major family entertainment facility as well.

Miami beach Mayor Rosen, alos an advocate of gambling, would prefer a major family attraction. "If we had it I would forego gambling," he said. "But at this point we don't have such an attraction." He doubts that a planned $40 million amusement park on Watson Island in Biseayne Bay will draw enough people.

There is also the question of the need for quick action.

"I think the chances are good that we will get a casino gambling issue on the ballot for November, 1978," said Rep. Steinberg. "With 11 hotels in bankruptcy or foreclosure now. Miami Beach can't wait."

Sharp opposition also comes from the Greater Maimi Chamber of Commerce. "It will attract a criminal element here and would exploit the weakness of our local citizens," said Les Freeman, executive vice president. "It's not a cure for Miami Beach's problems and it won't produce the bucketfuls of revenue as its backers say."

Although federal and state law enforcement officials have repeatedly reported a migration of reputed Mafia figures to South Florida to live, they have in the past usually acknowledged that Miami seems to be considered an "open city" by the mob - a place to play, not to "work."

Jay Dermer, a former mayor of Miami Beach who led a successful 1970 fight against legalized gambling in a city straw vote, agrees. "There is no way you can have casino gambling without complete infiltration of organized crime," he said. "This is well documented and well known to every law enforcement official. It would bring in loan sharking, pornography, hard narcotics. It would corrupt public officials."

Miami Beach doesn't need casinos. Freeman argues: other programs already in the works can rejuvenate the city without resorting to gambling.

"South Beach redevelopment is a big key," he said of a massive program to build a half-billion dollars' worth of hotels restaurants, shops, marina and other tourist-oriented facilities at the southern tip of Miami Beach. Other projects include the Watson Island amusement park, the current $65 million beach restoration work, renewed hospitality programs, hotel renovation and new direct flights to and from Europe.

Strong opposition to the casino gambling also is coming from owners of horse and dog tracks, who feel that the casinos would cut down their parimutuel business.

How did Miami Beach lose its glamor image as athe playground of the world? Competition and changing patterns in tourism are blamed.

The competition Hal Cohen, executive director of the Miami Beach tourist Development Authority, says sprang up when places like Hawaii.Europe and the Caribbean Islands became more accessible, and more developed. Walt Disney World took away much of Miami Beach's summer family business, though it has increased tourism through Miami from Latin America.

Another large factor was the condo craze. Thousands of people who used to come to Miami Beach for the winter as tourists in hotels bought condominiums. While they are still here during the winters, they no longer contribute to the hotel, restaurant and tour industry.