The Democratic Party must recognize that inflation is at the root of the nation's economic problems and begin to respond to "the concerns of the middle class, which pays for the programs for the disadvantaged," if it is to recover from its 1980 election losses, a senior aide to President Carter said yesterday.

In a speech to the National Press Club, Stuart E. Eizenstat, Carter's chief domestic policy adviser, also called for a reform of internal party structures and functions to give a larger role to elected Democratic officials, a willingness to remove the federal government "from certain sectors of American life" and a concentration on making Democratic-sponsored programs work better.

"The election of 1980 sent an unmistakable message," Eizenstat said. "The taxpayers of America -- the great American middle class -- are frustrated at persistent high inflation and its corrosive impact on their incomes and savings, their inability to buy a home, to plan for tomorrow, to retire when they hoped and, once retired, to maintain a reasonable standard of living. They are frustrated at heavy pockets of unemployment in basic industries which are losing their competitive edge. Many believe the Democratic Party has lost touch with their concerns. They took out their anger at those in power."

In the years ahead, Eizenstat argued, "Democratic policy must recognize the centrality of the inflation problem -- not simply as voter concerns, but as the root of our economic and unemployment problems." He said these policies should "encourage greater investment in productivity of both capital and labor," and cited measures for accelerated depreciation, increased support for research and development, a strong antitrust policy and "creative employment and training programs."

Eizenstat said the Democratic Party should not abandon its traditional concerns for the underprivileged and should "stoutly defend against any onslaught against those New Deal, Great Society and Carter programs that are working." But at the same time, he said, "we must reduce government-created constraints in the free market."

"Ultimately, it is no favor to consumers to attempt to protect them from reailty," he said.

Eizenstat also called for giving every elected Democratic member of Congress and governor a vote at the party's national convention and midterm conference, and a larger role in shaping the party platform in order to "reassert [the party's] role as a harmonizer and compromiser."

"The platform must not become the sum total of the maximum demands of every group," he said.