SIX YEARS ago there was some doubt whether the National Theatre would ever show plays again. Two years ago there was some doubt whether it would remain standing to show plays. Now, it not only has been saved from financial disaster and the wrecking ball, but has become a major force in Washington's latest theater wars.

The Kennedy Center is out: Its contract to book and manage the theatre was terminated three months ago. And the Shuberts, the country's largest theatrical organization, are in: hired to book plays the board hopes will make the National a theatrical showcase of the nation -- like the Kennedy Center.

"Only better," says the National's board chairman Maurice Tobin, sitting in his sleek law office overlooking downtown K Street. "You watch."

It is quite a promise. But then Tobin has developed a controversial reputation for saying what's on his mind and doing what he feels like -- including a major role in signing the Shuberts. So it's not surprising that he envisions the National featuring both New York shows and regional theater -- with each production in a five- to six-week run. "We're talking to Guthrie (in Minneapolis), the West Coast, Houston. You have to do some risky things," he says.

Will the Shuberts want to take risks? "We're obviously smart enough to let one chef do the cooking," says Tobin. "But we'll be watching. They've said they'll try very hard to get regional theater."

At least one board member has predicted Tobin will have his share of run-ins with the Shuberts -- who obtained a court order allowing them to book the National through the summer of 1981 -- and Tobin agrees: "I imagine, as in anything, there will be some boxing of ears." But he praises the Shuberts, who, he says, have guaranteed the National $100,000 a year and 50 percent of any profits above that, plus concession-stand profits for the first two years. Tobin says the Shubert organization also has lined up "Evita" for the National in September and the American premiere of "Amadeus" for the fall.

Tobin sees himself as one of Washington's theater pioneers -- along with the likes of Ford's Frankie Hewitt and Arena's Zelda Fichandler. "To walk into something that's already running -- that's no fun," he says. "I don't want to hang around the National after it's humming and booked and ready to roll. That's no fun. I'll want to go on to something else."

"He's attempting to build his own empire," says a board member. "Tobin's trying to make the National a little Kennedy Center." In the process, he has been described by those around him as "agressive," "abrassive," "not a diplomat" -- and much worse. And his personality has divided Washington's theater community and his own board. Ask people if Tobin is qualified to run the National and you get the following:

"Not in a civilized society," says one board member.

"Eminently qualified," says another. "He's one of the most adept people I've met."

But both sides seem to agree he is "a tough cookie." Ironically, some say he is cut from the same cloth as the man Tobin is most at odds with right now -- Roger Stevens, chairman of the Kennedy Center.

"Everybody owes it to themselves to do civic affairs," says Tobin. "I see this as paying my rent for a good life, a happy marriage -- whatever."

The National Theatre is the first major unsalaried "civic affair" in the arts for the 45-year-old attorney whose firm -- Tobin, Dillon and French -- specializes in "corporate law and financial investments."

Before 1974, when he became chairman of the board, Tobin had little theater experience. He was in the annual Hexagon show and in the American Lite Opera for a few years. In the early '60s, after graduation from George Washington University Law School, most of his time was spent working on the Hill, primarily as assistant counsel to the Natural Resources and Power Subcommittee of the House Committee on Government Operations. Later he served as counsel to the House Committee on Public Works. In those days he was a pioneer in environmental work, going around the country telling people who didn't want to hear it that they had to be environmentally responsible. It was hard then -- so it was fun, says Tobin. Later he went into private practice. Nine years ago, he married Joan Fleischmann, heir to the Fleischmann's margarine fortune. She is director of the regional office of Sotheby Park Bernet here.

Tobin got his chairmanship of the National Theatre literally for asking. Six years ago, Roger Stevens took over the National, assuming the lease held by James Nederlander, head of the major theatrical agency. The National was in dire straits: in need of repairs, good plays and lots of money. One of the people Stevens went to for money was Joan Tobin, who gave $5,000, as Stevens recalls. (Maurice Tobin Foundation, a non-profit charitable fund over which he presides. He also says one of Stevens' assistants asked them to get involved.)

Stevens then created the New National Theatre Corporation, a board of six people including both Maurice and Joan Tobin. He needed a chairman and asked for volunteers one day at a meeting. It was not a promising position, and most of the others at the meeting already chaired various organizations. Tobin chaired various organizations. Tobin raised his hand, and he got the job. "He can be a charming man," says Stevens. "But there was nothing overpowering about him except that I knew his wife and she gave us money."

Since then, Tobin has taken over an ever greater (and ever more controversial) role in heading the theater. One observer says that Tobin's unhappiness with the Kennedy Center began this way: "I think he became agitated when he saw the Warner getting big hit plays. Here was the theater across the street having what he couldn't have."

Tobin and some board members complained to Stevens and Martin Feinstein, then at the Kennedy Center and then booking the National.

Basically, Center officials have always argued that they turned the National Theatre around financially with the long runs of "Annie" and "Chorus Line." But Tobin and members of his executive committee say there were flops as well as long dark periods, including a six-month stretch in 1979. In addition, Tobin says, according to his figures, "Annie" grossed $2.9 million, of which the National received $144,127; and "Chorus Line" grossed $2.5 million and the National received $212,154. "It gave us money we didn't have, but who's to say we couldn't have had a contractual arrangement to make a lot more?" says Tobin.

Roger Stevens has vehemently denied any irregularities in management of the National.

Tobin has also angered his own colleagues through what are seen as unilateral actions. In October, for example, he helped add 10 new people to the board -- many nominated by Tobin or the executive committee -- who are regarded by some as Tobin's biggest supporters. According to one board member, some of the nominees were listed as being sponsored by board members who later said they didn't even know the people. Tobin admits that probably happened: "I couldn't remember who suggested whom."

Another case: After the National board voted to sever relations with the Kennedy Center, they received proposals from various organizations, including the Shuberts, with whom they voted to pursue negotiations. There was never a further vote, several board members agree. One day Tobin showed up at a meeting with the Shubert heads in tow and later held a press conference to announce the new arrangement. "The boar to this day has not seen the agreement with the Shuberts," said a board member. "The board had a number of questions about the Shuberts."

"The major parts of the contract were spelled out at the vote," said executive committee member Donn Murphy, an orginal board member, Tobin adamantly agrees. Says Anthony Hope, a new board member and a friend of both Tobin and Roger Stevens, "I'm not sure I'd want to see the final contract. There are only four of us on the board who are lawyers."

"I haven't disagreed with his decisions," says Hope. "But I often disagree with the way he makes his decisions public. He seems unnecessarily scrappy. I don't think it's deviousness. He's used to fighting for his theater."

But some say he pushes solely for himself -- anywhere there is a place to make a problem worse, he does. "In many respects, he is the controversy," says one board member. Roger Stevens agrees: "He created the controversy between him and me. I had no quarrel with him." Stevens feels that Tobin double-crossed him like no one in his whole life has. "They had a legal right to terminate the contract," he says, "but not a moral one." Tobin informed Stevens of the termination four days after Stevens suffered a heart attack in San Franscisco.

Tobin can be "theatrical" as one observer noted. At National openings, he glides through, making every guest feel like he is the most important. His peculiar nasal voice and extensive hand gestures are his trademarks, and he is clearly the host. But always he produces contradictory reactions.

"Maury is a saint," said the National's general counsel, Joseph Fontant. "I saw him at the opening of 'Snow White.' The cast was there. Snow White was tired. But Maury led my two kids up to shake her hand. He didn't have to do it. It was one of the most beautiful things I've ever seen."

National board treasurer Gerson Nordlinger, a longtime local patron of the arts and one of the original members of the board, resinged recently. In a letter to the board explaining his resignation, he wrote that the "vindictiveness and derisive language toward me from Tobin . . . I find unparalleled in my more than 30 years of community service."

Tobin is aware of his abrasive effect. "I think meanness with a purpose is okay," he says nonchalantly. "I think when you have genuine differences, fresh air is the best purgative."