Washington — Two hundred years after the formulation of the American constitutional system dividing power among three main branches of government, a group of former Cabinet-level officials are urging the United States to replace that system with a modified parliamentary plan.
Lloyd Cutler, former counsel to President Carter, former Treasury Secretary C. Douglas Dillon, Bryce Harlow, counselor to President Nixon, former Defense Secretary Robert McNamara, and other prestigious political figures are arguing that the present system is confused, deadlocked, and dangerous. They urge that forthcoming celebration of the Constitution's bicentenary throughout the late 1980s should be joined with an effort to modify the system. With modest funds, they are organizing a ''Committee on the Constitutional System'' with headquarters here, under the auspices of the National Academy of Public Administration.
The first gathering here of the group of about 35 former officials, academicians, and politicians coincides with America's 1982 midterm election. Some say the election illustrates the ambiguities in the current system: an election in which a lot of money is spent, special interest groups are prominent , half the public doesn't vote, and interpretations of the results are conflicting.
The invitation to the meeting noted that the nonpartisan group ''has been formed by some of us who believe that the causes of deadlock are less in the qualities of our elected leaders than in the unique separation of executive and legislative powers established by the Constitution.''
At group discussions, speakers declared that the US is alone among democracies in having separation of powers, which was instituted by colonists fearful of the authority wielded by George III. Elements of the British or Canadian parliamentary system - under which the executive officers are chosen from the ranks of the legislature - were frequently cited as alternatives to the separation of White House and congressional powers in Washington.
Charges of governmental stalemate have increased in Washington and seem likely to increase following what some will see as a inconclusive Nov. 2 election. In a speech at Tufts University last May, Mr. Dillon assailed ''the inability of our present system to clearly place the responsibility for action in any one place.''
Lloyd Cutler, writing in Foreign Affairs Quarterly in 1980, called the situation dangerous, and urged ''appointment of a bipartisan presidential commission'' for study. ''In each administration,'' he charged, ''it becomes progressively more difficult to make the present system work effectively . . . .''
The new, ad-hoc committee recessed its two-day session here without formal action but with the promise of funds from outside organizations. The group, in ''a proposal for a bicentennial review,'' observed in passing:
''A governmental structure deliberately designed to frustrate a despot who seeks to assemble its powers for evil purposes must also, inevitably, frustrate democratic leaders who have been chosen by the people to exercise its powers for good and worthy ends.''