The Marshall Plan succeeded because of an unusual spirit of cooperation--in the United States and abroad--that is very difficult to duplicate in present-day foreign aid programs, a panel of foreign policy experts said yesterday afternoon.

The United States plan to revitalize the European economy after World War II--announced by Secretary of State George C. Marshall at Harvard's Commencement in 1947--represented "the most successful foreign policy initiative that the United States has mounted since World War II," said Professor of History Charles S. Maier, who served as moderator.

The $13 billion, four-year aid program was successful even though it provided only a fraction of the necessary capital because all it had to do was "clear bottlenecks and let society recover," Maier told the crowd of about 50 people. He added that American money acted "like oil in a machine. It helped to alleviate the constraints [on economic growth]."

However, panelist Hollis B. Chenery, Cabot Professor of Economics Emeritus, said that the program will be hard to apply elsewhere because its success was dependent on the ability of the European governments to work together. "It is much harder to establish [collaboration] in other situations," he said.

Although the World Bank attempts to maintains the spirit established by the Marshall Plan, its "job is more difficult. Now we have 20 or so donors instead of just one. It's more complicated politically," said Chenery, who worked in the Paris office of the Marshall Plan.

The aid program succeded because "it represented a far-reaching consensus between [all parts of the American government]" which rarely exists today, said Stimson Professor of Law Emeritus Milton Katz, who ran the Paris office during the last two years of the Marshall Plan.

Katz criticized President Reagan for trying to conduct foreign policy without the Congress's support. To create a workable foreign aid program, "you have to line up support in the White House and on both sides of the aisle so that it will be continued," he said. "The idea of saying 'these people in the House and Senate have wrong views so I have to go around them,' is nonsensical."

But building a consensus requires so much time and energy that it can only be attempted in a real state of emergency such as the one that existed in the 1940s, said Charles Kindleberger, Professor of Economics Emeritus at MIT. "Marshall spent all his time travelling around the country. It was thought to be a crisis. You can't treat everything as a crisis," he said.