Scenario Season has come to the District Building, a time for politicians looking ahead to the 1982 city elections to play Machiavellian musical chairs and dream of various ways to divvy up the spoils. m

So when Mayor Marion S. Barry had a cozy dinner with City Council Chairman Arrington Dixon and his politically active wife Sharon at the Jefferson Hotel awhile back, an unexpected possibility emerged: a mutual support pact, in which one of the most often-mentioned contenders for the mayor's office would instead support Barry's anticipated reelection bid.

"We might just support the brother," a Dixon insider said of Barry, who because of his recent political problems has been considered something of a sitting duck. "Marion just might have people closing ranks behind him."

A few days later, the source offered another scenario that down-played the likelihood of a Barry-Dixon alliance. But the notion, still alive, is an intriguing one that says a lot about how District politicians view their city and the preeminence of animosity as a basis for cutting deals.

The rationale for a pact between Dixon and Barry is that black Washingtonians must unite behind someone or run the risk of losing even their current limited-home-rule control of the city to whites, or to a black candidate controlled by whites. For Barry, such a deal would neutralize a possible opponent and possibly widen his base; Dixon probably would receive support in what might be a tough reelection campaign, and would be heir apparent in another four years.

The ironies are delectable. First, there is the notion of the Dixons and Barry as stalwarts on the last line of defense for black rule. Although Arrington Dixon boasts of his roots in Southeast, he has been known to be as welcome on a street corner in Anacostia as a Moral Majority coordinator at 14th and U. Sharon Pratt Dixon comes from an old-line blue-blood family, and the couple lives on one of the last streets in Washington, just inside the Maryland line near Rock Creek.

Barry is on equally shaky ground. He was perceived as the candidate of the "white establishment" last time around, and -- in the eyes of many -- would have to pirouette on a dime to run next time as a last-hope black candidate.

There is also the irony of these old enemies sitting down all chummy to a meal. It was Barry, not Doug Moore, that Sharon Dixon -- a poised and proper devotee of hardball politics -- was referring to when she said a couple of years ago that black officials who would "split their verbs or be soft on their d's and t's in front of Queen Elizabeth" were an embarrassment to Washington.

And the antipathy has been mutual, with Barry's aides recently grabbing anyone who will listen to tell them that the Dixons are the ones responsible for all those rumors -- the ones that say because of possible fallout from the ongoing investigation of Youth Pride, Inc., Barry might not even be around in '82.

If Barry is welcome back into the fold of black solidarity, then there must be a new villian . . . and there is: John Lamar Ray, the country lawyer from Tom Creek, Ga.

Black politicians in this town see a Present Danger. They see black families, voting families, moving out to the suburbs, and they see whites taking their places and transforming neighborhoods like Capitol Hill and now Shaw. They see white politicains, like council members Betty Ann Kane and David A. Clarke, becoming more and more visible.

And with great interest they watched newcomer John Ray retain his council seat last year with the help of a slick fundraising apparatus drawn substantially from the same group of whites whose support tainted Barry in many eyes in 1978.

But in some circles, Ray's transgressions are even more grievous than Barry's. He teamed with Kane this summer to secure for himself the chairmanship of the D.C. delegation to the Democratic National Convention. It was a largely ceremonial post that De. Walter E. Fauntroy, the usual Master of such Ceremonies and a friend of the Dixons, sorely wanted.

And recently, Ray sparred with Dixon over reorganization of the coucil, attempting to secure for Kane or for himself a coveted committee chairmanship that Dixon wanted to award to another of his allies, Charlene Drew Jarvis.

Barry, too, has good reason to be angry with Ray: He has usurped much of Barry's old organization, leaving the mayor with a cadre whose loyalties are at best divided.

Sources close to the Dixons now say that even if detente with Barry fails, the mayor still isn't top priority. The Bad Guy of the moment is Ray.

All of which goes to show that the real enemy is the latest enemy. The one visible between the sights.