AFTER BARELY ENOUGH outings to mature

into a genuinely mediocre team, Washington's revised and overextended ambassadors to the North American Soccer League--the Diplomats--died quietly over the weekend of financial anemia. Total time elapsed: about six painful months since the second coming and the city's last red-carpet welcome to this natural market for the sport. Prediction for next summer? Try cricket on the Ellipse.

Let nobody blame the people of Washington for this flop, either--neither the league nor the team had its act together and until that happens, soccer for adult professionals will continue to be a sometime thing on this continent. In fact, the deaths of a fistful of teams this year may be mercy killings, in that the pool of talent and the markets for it needed some consolidation.

That said, Dips II never did seize the right opportunities or advice to prosper in this town--where soccer is popular. The 1981 "Diplomats" were really another team slightly reconditioned; they arrived here F.O.B. Detroit and vanished without portfolio or even whimper. The many business and civic leaders who fought so feverishly to save the original team had let it be known early on that too much emphasis on high ticket prices, low-to-no-promotional campaigns and bank-breaking salaries for superstars could kill all but hard-core support for this year's Diplomats. As they say on the field, so it came to pass--but no score.

We still believe that Washington can be good to professional soccer and vice versa; attendance in the Dips I days showed so. And with more than 120,000 youngsters playing in organized leagues around the region, there's a growing interest for you. But unless and until a dedicated group of investors--with the patience of Job and the talents of Pel,e in his heyday --can be organized and committed to truly professional soccer in the nation's capital, there is no point in playing any more games with the fans.