The local prosecutor who ran the south Florida investigation calls it "successful." A federal drug enforcement official called it "illegal."

At one point, while it was underway, relations were so strained that the Dade County state attorney and the top area Drug Enforcement Administration official on the case were threatening each other with arrest.

The troubled joint investigation did lead to the arrest of scores of alleged drug smugglers this month, after its legality finally was sanctioned by the Justice Depeartment. But it is hardly an example of federal-state cooperation that authorities would like to cite as evidence of their attack on the growing drug trade in Florida.

The controversy centered on federal concerns that state investigators-who had infiltrated smuggling groups posing as crooked cops-were letting unacceptably large amounts of drugs be sold on the streets. DEA guidelines permit only-small, controlled amounts to be distributed.

Dade County State Attorney Janet Reno said in a recent phone conversation from Miami that she feels the federal animosity may have stemmed more from jealously that her office more from jealousy that her office was taking the lead in an innovatice investigation.

Federal authorities have been reluctant to discuss the controversy. "I'm not goint into the who struck John," said Charles F. C. Ruff, an associate deput attorney general familiar with the case.

Reno is less hesitant, perhaps because she was stung when DEA and Customs Service memos critical of her investigation were leaked to the St. Petersburg Times.

The Dade County "Sting" operation began mildly enough last summer, when Reno's colorful chief investigator, Martin Dardis, got a court-approved "bug" on a suspected cigarette smuggler.

The hidden mike collected enough information to confront the suspect, Ronald Braswell, and convince him to becom an informant. Other microphones and a videotape camera-the hallmark of most successful "sting" investigations-were installed in Braswell's office to record illegal transactions.

The investigation turned toward drug smuggling when Braswell started branching out. It was then that Dardis and another investigator, William Riley, got the idea of infiltrating the suspected drug rings, posing as policemen who would take bribes to provide the smugglerswith a safe airport.

Reno said she told federal authorities about the plan because the smugglers would be crossing state-indeed intenational-boundaries. "I was seeking a consensus to push what I saw as a golden opportunity," she said.

What she got was complaints. DEA and Custom Service locally criticized her investigators' scheme. So Reno took her case to Washington.

Philip B. Heymann, head of the criminal division at Justice, wouldn't approve the idea of letting drugs go to the streets. Thus, when a DC3 airplane loaded with marijuana headed into the supposedly safe airport guarded by Dardis and Riley on Dec. 18, a Customs helicopter was on its tail.

The resulting confusion almost destroyed the undercover operation and Dardis and Riley, according to Reno. Riley had to stop an armed smuggler from shoting down the helicopter, and the DC3 was waved off.

In the aftermath, Reno said, she got in a shouting match with regional DEA head Frederick A. Rodey. "He threatened to arrest my men. And I said, 'If you do, I'll arrest you for obstruction of justice,'" the local prosecutor recalled.

More meetings finally resulted in a Jan. 12 agreement by Justice approving the Reno operation.

Justice spokesman Terrence B. Adamson said diplomatically that there were "tensions and misunderstandings, but the operation was successful."

"Due to differences in approach and operating procedures, there were disagreements - sometimes strong - about how best to proceed," he acknowledged.

It finally was decided that the law enforcement benefits outweighed the risk of allowing drugs to be distributed, Adamson said. "We concluded that it was not illegal under the circumstances, though it was a departure from general practice."

Even with the blessing of Washington, a final coordinated state-federal operation degenerated into accusations. In late January, a planeload of marijuana and Quaalude pills landed at the safe field. But more than 80,000 pills were lost to the streets when federal agents following a suspect lost the trail.

Each side blamed the other for the mixup.

A final blunder came when other local authorities with a search warrant for the rest of the smuggled Quaaludes walked directly to the trunk of a car where Dardis had told them he'd hidden the pills.

While Reno and her staff were trying to prepared cases from the now-blown undercover operation, a reporter for the St. Petersburg Times came up with Customs and DEA memos critical of the operation.

In one, an aide to DEA chief Peter Bensinger, called the operation illegal. In another, Reno said, she was described as hysterical.

Reno now feels that the controversy has died down. "They [federal authorities] just didn't understand what we were trying to do," she said. "But this wasn't something off the wall. We didn't entrap anyone. It was carefully researced."

Reno admits she's concerned that defense lawyers will seek the critical federal memos in an attempt to show the drug "Sting" was illegal. But she said she believes the cases will stand up.

And next time? "We've all learned a lot from the experience," she said.