Southeast Washington, which is chafing over temporary cancellation of construction plans for the part of the inner city subway scheduled to run through this east-of-the-river community, is a cacophony of contrasts.

Rotting apartments sit across from spanking new town houses. The best view in the city is obtained by driving past boarded-up buildings. With its acres of public housing and cheap apartments, Southeast Washington is the haven for the poor. Yet it has its share of $100,000 houses on cul-de-sacs and avenues, houses that would cost twice as much in more prestigious sections. It has some of the city's most astute residents along with some of the most deprived and indifferent.

Anacostia, perhaps the most well-known section of Southeast, is poised on the brink of change and the Green Line subway is a metaphor for that change. Talk to residents about the current subway snafu and a contrast of opinions emerges.

Some people, somewhat predictably, wonder whether it will be built at all because so many of the residents are poor and black. This subway, they believe, is strictly one for suburban commuters. ("We knew they wouldn't build a subway here," said one high school student, "because who would go underground out here at night?")

But others are thinking of the future. They see the current uncertainty--a dispute over a route change that is being challenged by Prince George's County businessmen and Reagan's budget ax--as merely a temporary hurdle, one more stumbling block in this isolated and depressed community's forward move toward rejuvenation.

They know it will bring on displacement and the possible loss of local businesses; they know that it is inevitable that there is likely to be speculation in anticipation of increasing property values.

So the unspoken message, the one these people talk about only when pressed, is that Anacostia is going to pay a high price for progress.

You can't shake this painful paradox as you walk and ride around Anacostia. On the one hand, the subway will be a financial blessing, but on the other hand, it will bring severe displacement. Housing and economic discrimination have herded blacks into Anacostia's ghettos, and Washington communities somehow never are redeveloped if their residents remain predominantly black and nonaffluent. It's a dilemma that seems to go beyond property values and tax bases.

True, the value of everything in Anacostia will increase the moment ground is broken for the subway. But why can't this time be different? Anacostia is primarily a community of poor blacks. Everyone in city hall says that building the Green Line is the number one priority, and most of those in city hall are black. Why can't city hall make sure that this time, this long-neglected black community get something from the establishment--a subway without major disruption of its people and businesses?

Even the most optimistic of residents don't think it will.

"The Navy is thinking about moving 30,000 employes back to the Navy Yard," says John Kinard, director of the Anacostia Museum on Martin Luther King Avenue. "Where are these 30,000 people going to live? They're going to displace Anacostia residents who are renting. It is going to be a reactivation of the history when Anacostia was created to serve the Navy Yard. Our people will be moved out--back to North Carolina. Here is the last place for speculators--it will take place here."

Seventy-one-year-old Almore Dale, a retired Howard University accountant, is a willing tour guide on a recent visit to Anacostia because it is the neighborhood in which he grew up. He talks as he steers his big Oldsmobile with the low license tags along the disputed route of the Green Line, along Southern and Alabama avenues.

I ask him about the future.

"I'm positive this area is going to grow and thrive with time," he replies.

I ask him if it will grow and thrive for the people who now live there.

"No way. But that is the name of the game. It's depressing in a way. We're in transition. We've been way down. We now have all of the central services that are necessary for renewal . . . It's ready for human development. I have mixed emotions in that many will suffer and will be displaced."

"Any country that advocates the kinds of things America does should be able to find a way to eliminate these problems," he says. "But what can you do?"