D.C. Mayor Marion Barry yesterday strongly defended his intervention into the fight over the city's daily numbers game contract, while assailing lottery board chairman Brant Coopersmith's leadership and calling board member Jerry Cooper a liar.

Barry, contending the lottery board repeatedly ignored the city's best legal advice on awarding the contract, complained that Coopersmith "has not given the leadership I expected him to give" and has misrepresented the board's positions at various times during the protracted dispute.

"What we've got here is a board where every other day one or two members change their mind," Barry said in an interview, which he requested, with Washington Post editorial writers and reporters.

The mayor said he objected to the board's March 15 selection of Lottery Technology Enterprises over two other bidders to operate the numbers game, because "we don't know whether this is a black front" for white owners.

But Barry also strongly denied allegations that he or members of his administration attempted to steer the lucrative contract to personal or political friends involved in Columbia Gaming Services Inc., one of the losing bidders.

The firm, which submitted the most costly bid, is represented by attorney Robert B. Washington Jr., a Barry political ally and former city Democratic party chairman. The other losing firm was D.C. Data Co.

"I don't make decisions based on political friendships," said Barry, who was accompanied for the 1 1/2-hour interview by City Administrator Elijah B. Rogers and by Ivanhoe Donaldson, the city's deputy mayor for economic development, who has played a key role in the dispute and who vacationed recently with attorney Washington in Antigua.

Barry said that he would have supported the Lottery Technology selection if the board had agreed to ask the firm to document its minority participation. But he said the board refused.

Coopersmith said yesterday that the board rejected that request "because we would've had to open up the negotiations for everyone," not just Lottery Technology.

Coopersmith declined to respond to Barry's assessment of his leadership.

Barry said he did not get involved in the dispute until April 18. He said the quasi-independent board requested Donaldson's advice at a March 7 meeting before making its selection of Lottery Technology. Barry said he had no role in Donaldson's appearance at the meeting, although at the time he said through his press spokeswoman, Annette Samuels, that he had requested that the board listen to Donaldson.

Barry, reminded that board member Cooper, among others, said the mayor had called about the Donaldson appearance, said that Cooper does not talk very much, but when he does, "he's a liar."

Cooper said yesterday, "I was in the shower when he called. That's why I remember it so vividly."

After weeks of court fights, behind-the-scenes squabbling over the contract and intense pressure from Barry and his aides, the lottery board last week reluctantly agreed to seek new offers, while maintaining that its first selection process was not flawed. Lawyers for Lottery Technology are contesting the resolicitation in two court cases, one of them a $12 million suit claiming that Barry's key aides conspired to give the contract to Columbia Gaming.

Donaldson said yesterday that after initially reviewing the three proposals he thought D.C. Data had submitted the best overall bid. But after further study, he said, he concluded that Columbia Gaming's offer was best. Donaldson said he was never asked by the board for his opinion and never volunteered it to board members.

Barry and Donaldson said they both personally know members of all three bidding companies, but the mayor said he has not talked to any of the representatives of the bidders about the contract.

Donaldson said specifically that he did not discuss the lottery contract with Washington during their mid-March vacation in Antigua, although he said that the two men and their wives "had dinner together nearly every night."