For the last 31 years, Marvin Miller has been negotiating for the uniformed masses.

The first 16 years, he bargained for men and women in working clothes and hard hats, the more than 1.25 million who belonged to the United Steelworkers Union.

The last 15 he has spent negotiating for those in baseball jerseys and batting helmets, the 650 members of the Major League Baseball Players Association.

Miller, whose only uniform is a business suit, says there is only one thing the two unions have in common -- the bargaining table.

"The difference between the two can't be overexaggerated," said Miller, 64, executive director of the players association since 1966. "The steelworkers' union had been established for many years and had a staff of more than 1,000.

"The baseball union existed only in name. It was a small organization with no real staff and a bank account of $5,400 that was kept in a file cabinet. It had no collective bargaining and no grievance committee. The players were being used as pawns. I looked at it as a challenge.

"The steelworkers' union negotiations always had a far greater impact on the economy of the country than the baseball negotiations. But it probably got 5 percent of the attention that the baseball strike has received. I'm well aware of the kind of focus and artificial spotlight that is placed on baseball."

Miller has been in the spotlight, it seems ever since he came to baseball. Since 1966, he has been the man the major league players have looked to for instruction and help, from their battle to eliminate the reserve clause in 1969 to the establishment of pension benefits (and the first strike) in 1972 to the compensation issue of today.

Since Miller's entrance into baseball, the major league players have reaped large benefits. The two events are not unrelated. The minimum major league salary in 1966 was $7,000. Today it is $32,500. In the same period, the average salary has risen from $22,500 to $170,000. The top salary has ballooned from $150,000 a year to Dave Winfield's $1.5 million-a-year contract.

Over the last 16 years, Miller has been called everything from Svengali to the most powerful man in baseball. His name is as revered as it is chastised, depending on whose side you're on.

Nowadays, the players, the salaries and the reason for the strike are different from 1972. But one thing has remained the same -- Marvin Miller is a most provocative figure.

"I don't think I have changed any in the past 15 years I have spent in baseball," said Miller, a native New Yorker who spent three years at Miami (Ohio) University before graduating in 1938 from New York University with a degree in economics. "I think I am the same negotiator now that I was in 1966. I don't know, though. You would have to ask the people around me if I have changed.

"I don't claim sole credit for all of the gains, but I think I have had a lot to do with them. Aside from the economic improvement, there has been a development and maturity in the players, as I look back. That's a source of great satisfaction for me. I think in that respect I have had a more lasting quality."

Now, Miller is almost ready to negotiate something else: his future.

"I have been thinking seriously about retiring," said Miller. "I think if last year's settlement had included everything, I would have retired already. I would say that perhaps I might retire within a year after this has all been settled."

Miller says he would not leave the current negotiations unfinished. And he is so devoted to the players' cause that he says, "Even when I leave, I would like to stay on and help in whatever capacity I could.

"When you have led a structured existence as I have for 40 years, you look forward to a rest, to break away from it," Miller said. "I am going to try my hand at writing, I think. I don't know if I have the self-discipline, but I'd like to try. I would want to write on labor management or maybe the baseball situation. I would also like playing tennis and maybe taking some trips with my wife Terry (Theresa)."

Because he has been functioning at a nonstop pace for so long, such a relaxed atmosphere would seemingly take Miller out of his natural habitat. Before the steelworkers' union, he worked for the United States Conciliation Service, the National Wage Stabilization Board and, during World War II, the National War Labor Relations Board.

Now, he is involved in a war of a far different nature. "Here we have people (the players) who have been entertaining millions of people and the owners are treating them like property," he says. "Does that seem fair to you?"