As the Central American issue is once more illustrating, there is no greater force in governmental life than the momentum of a policy under fire - particularly one in which a president is personally involved.
In the case of Central America, the policy undoubtedly flows from the conviction of President Reagan and several of those around him. Their reaction to criticism, however, is much less to reconsider their policy than to defend and explain it. They are pushed in this by their parallel belief that the problem is not one of substance but of a lack of public comprehension. Their task is helped immeasurably by certain basic pressures and inhibitions in bureaucratic and political life.
The recent accounts of a memorandum prepared for a National Security Council meeting on Central America on June 8 appear to illustrate the point.
There has been broad public skepticism about the administration's view of the conflict and the resultant policies, opposition to funding in the Congress, and the quiet detachment of most of our allies. But the memorandum, as reported, gives no suggestion of a review of the basic premises of the policy.
The Defense Department is said to be suggesting a pullout but only to avoid a policy failure. This could be less a genuine option than a ploy to force support for the defense position that a greater military effort is required.
The policy memorandum appears to accept without challenge the premise that the issue is fundamentally one of blocking Cuban/Soviet efforts and that these efforts are basically the root cause of the troubles in the area. The thrust of the paper is how to pursue current policies with greater success. There is no apparent hint that the lack of support for the policies may be due to the premises of the policies themselves.
The history of US foreign relations during the years of our active postwar engagement is studded with similar examples of the unwillingness of an administration to look candidly at the premises of policies in trouble. Vietnam and our dependence on Iran are two cases in point.
Policies become vested interests of those who create them and pursue them. It becomes personally risky to suggest to a president, in midstream, that a policy needs to be reexamined. Those who may be tempted are deterred by the prospects of being labeled ''indecisive,'' ''vacillating,'' ''weak,'' or ''inconsistent.''
The problem is aggravated by the increasing incidence of leaks. Leaks that reveal divisions over how to pursue policies are less damaging politically than those that reveal a fundamental debate over the correctness of the policies and the premises that underlie them. They give dangerous ammunition to outside, partisan opponents. Few policy papers are written today in the government without a consciousness of the problem of unauthorized disclosure.
Then there is the team aspect. If the policy opponent be a political appointee, that person's pronounced opposition to a policy premise can bring charges of failure to support the team; the results can be ostracism or dismissal.
The career official who is sufficiently placed to question policy is even more vulnerable. Charges may include the fact that the official is a ''holdover, '' disloyal to the present administration, that he or she is unsympathetic to a new and ''tougher'' approach. Exclusion from any meaningful role in the process can quickly follow.
The process of assessment itself inhibits reconsideration. While it would be unfair to suggest that participating intelligence agencies tailor their assessment of a situation to fit the policy, it is only human that, in a bureaucracy - including that of foreign policy and intelligence - agency representatives will have their ''turf'' in mind. Intelligence agencies may tend to paint the picture darker than others in order to be ''protected'' against sudden changes. Defense agencies may tend to highlight the ultimate need for military force. The National Security Council input will almost certainly reflect a consciousness of the president's political needs. The State Department will hesitate over conclusions that may have serious foreign policy implications.
Finally, the momentum of a policy gains through the reluctance of political opponents, especially in the Congress, to attack a president's policies. This reluctance may stem from the perceived popularity of the president. It may stem even more from the fear that, if things go wrong, those who block or restrict a policy may be blamed for the failure. A president can claim that, had he had full support of his views, US interests would have prevailed. It was the opponents and the ''doubters'' who were responsible for an American loss. This is a significant inhibition.
In the policy debates today over Central America within the administration there are probably many questions that are being muted - if they are being asked at all. ''If the policies are not receiving domestic support, are there fundamental weaknesses in the premises that should be addressed?'' ''Is the buildup of Cuban presence in Nicaragua (reported in the paper) the result of further aggressive designs or a reaction to their perception of what we are doing?'' ''Why do we not have firmer, clearer support from the bulk of Central American states?''
A bipartisan commission on Central America has now been established. Such an idea undoubtedly stems from an administration hope that these inhibitions will work in such a commission and that opposition will be further blunted by the appearance of a bipartisan consensus. If this happens, the commission risks joining others like it that have merely added to the history of governmental reluctance to ask the hard questions about policies under challenge.