The "liberal consensus" of the last half-century faces a critical turning point during the next decade, three professors and a public opinion expert agreed last night, but they differed over why it has lost popular support and how liberals can regain influence.

"The future of the liberal consensus is at stake--it's coming apart very rapidly," Daniel G. Yankelovich, '46 president of a prominent public research organization, told an Institute of Politics (IOP) audience of about 350 in his 35-minute opening address.

Yankelovich said the difficulty of maintaining appeal for the political center has threatened the dominance of the liberal consensus--which he defined roughly as the supporters of the presidential bid of Sen. Edward M. Kennedy '54 (D-Mass.)--largely because of the impact of "spectacular success" of earlier liberals in raising the national standard of living.

Because of four decades of prosperity, Americans have adopted a "psychology of affluence--the 'we have a right to expect more of everything' outlook," Yankelovich said, adding that liberal demands for higher taxes and greater sacrifice have caused centrists to support "negative" neoconservative measures.

Dismissing the neoconservative approach as "too angry" and unconstructive, Yankelovich counseled liberals not to "give up" or to fight for outdated liberal programs, but to "regroup and rethink" to find new means for solving traditional liberal goals like social welfare and national growth, which "are as valid as ever."

But John Kenneth Galbraith, Warburg Professor of Economics, outlined new issues for liberals to address, adding that their "marked failure in dealing with the oppressive problem of inflation" and of coping with the "great shift in the substantive character of the economy," notably the rise of influential great organizations like OPEC.

"Inflation causes a feeling among people that something has been taken away--nothing stirs that attitude like inflation," Galbraith said.

Citing economic woes as the principal cause of the center's disenchantment with liberal ideas, Galbraith said that liberals, "once having solved those economic problems, won't find other (traditional) liberal areas where there is any great demand for retreat."

Galbraith noted liberals' "better tendency than conservatives to accommodate to circumstances," adding that "a large segment of conservatives value a romantic return to the 19th century" that the liberal consensus is likely to return once it finds solutions for economic problems, which he said are responsible for "the difficult travail of liberalism at the moment."

But Thomas C. Schelling, Littauer Professor of Political Economy, said the "liberal consensus sure doesn't seem to have more of a present," adding it has lost appeal as people have become "utterly selfish" about issues like the sharing of energy resources with less-resourceful allies.

Inflation, a lost of trust in the presidency, and this self-centered "new isolationism" have all worked against the maintenance of liberal influence, Schelling said, but did add that today's "upset and disgusted" populace has failed to keep a sense of historical perspective.

"It's hard for me to imagine anything quite as scary as things seemed to be in the 1930's" Schelling said, adding, "I don't really expect things will be so bad as the past."

Richard E. Neustadt, Littauer Professor of Public Administration, also cautioned against assuming liberalism is permanently dead, noting that if a new form of technology can be found that will cheapen energy prices, "the psychology of America would change drastically."

Using historical examples to show that "specific programs that follow the liberal impulse take a long time to germinate," Neustadt said a "new agenda" for liberals will eventually emerge, though probably not soon.

Like Galbraith, Neustadt singled out the area of "economic management" as an essential feature of this new agenda, adding that he sees "nothing sufficiently constructive" in conservative suggestions to make it likely the right wing will supplant the liberal consensus