Sidney Hilman, Franklin D. Roosevelt's labor ally, many years ago defined politics as the science off "who gets what."

That is still the essence of the game. Huge shares of the nation's wealth are being bartered here in transactions between the Democratic Party and the special interests.

Shall $30 billion to $100 billion be diverted to the weapons industry and its workers for the MX missile? Shall $65 billion a year be transferred to the $400 billion medical industry in the form of a national health care plan? Do the railroads get $1 billion and 20,000 jobs for a modernization program?

Do the car makers, the steel companies and the shipbuilders get new federal billions in compensation for hard times and foreign competiton? Does the housing industry get a crash program of 200,000 federally subsidized low-income and middle-income homes to help it out of the economic slump?

Does the party want to add another 1 million workers to the unemployment compensation rolls by liberalizing the law? Do you put $12 billion into an antirecession program to create 800,000 public service jobs, largely for blacks? Do you expand the coal industry on behalf of the mining corporations and the United Mine Workers through a new energy program?

Those are the decisions being made this week and, if they resemble the agenda for Congress or the state legislatures, that is no accident.

To a considerable degree, the parties are little more than coalitions of interest groups. There are, of course, high-minded and idealistic individuals with no special economic axes to grind. But in the main, the delegations are motivated by money interests.

Roughly 50 percent of the delegates here are women. Their prime interests are in affirmative-action programs that mean jobs, promotion, money.

The black and Hispanic caucuses have interests along the same lines. They seek bigger shares of the enormous federal procurement budget, and new laws and federal agencies to advance their economic status in American life.

The lobbies of the poor want to add 5 million children and 200,000 women to the Medicaid rolls.

Working mothers want federally funded day-care programs.

Federal workers want to protect their wage levels.

The elderly have a host of economic objectives from Social Security benefits to housing and feeding programs.

The labor unions are seeking new federal weapons in their battles to organize the work force.

The veterans lobby wants expanded benefits and allowances.

Exporters want federal assistance to compete in international markets.

There are proposals for tax cuts for the rich, the poor and the middleclass.

The grain growers are promised a 500-million-barrel share of U.S. energy supplies in the form of ethanol.

The National Education Association, with about 400 delegates here, works from within the party to get larger shares of the public treasure in the form of dozens of new federal programs.

That's what the platform debates and the platform votes are all about. The Democrats have tried to accommodate virtually all of these divergent and often conflicting interest groups in the promises and language of the platform. The problem, of course, is that along with these special-interest accommodations the party also seeks an accommodation with that larger public called "the taxpayers." Thus, the platform promise to "support the discipline of attempting to live within the limits of our anticipated revenues. dGovernment must set the example of fiscal responsibility. . . ."

The drafters of the platform, however, are not under similar constraints.