THE FIGHT over rent control for Cambridge waged around City Hall during the past few weeks has been one of the most emotionally charged disputes ever to take place in the City's politics. Especially for its proponents, rent control came to be a symbolic showdown, a last ditch struggle against the forces which have been inexorably transforming the Cambridge they have known into a new City--one which they are best regard suspiciously.

The signs and the rhetoric with which the steps of City Hall were filled during the Cambridge Housing Convention's vigil there all the story well. There seemed to be no middle ground for those pushing for rent control. A poster pictured the hands of nine city councillors: the hands of the four councillors who voted for the housing convention's rent control ordinance are clean; those of the five opposed are splattered with blood. As housing convention vice-chairman Bill Joyce saw it, the four backed "the little people of Cambridge," while the five voted for "rent gougers, speculators, banks and Harvard and M.I.T."

The debate within the council chambers was much the same. Discussing rent control as an issue of public policy is difficult at best, for its consequences are highly ambiguous and an overall evaluation depends mostly on the weight one places on their various aspects.

Rent control protects some tenants somewhat against rent increases, though which tenants are really helped and the extent of their protection remain unclear. It does tend to hurt landlords, though clever speculators can usually find a way over, under, or around such a law, creating a black market in housing. It hampers new construction, and consequently reduces a city's potential tax base (and the amount of money it has to spend)--but the time needed for major damage to new construction is primarily guesswork. On paper, rent control laws are an added weapon for building code enforcement, but they are also a major inducement for increasing deterioation of buildings.

That is about 90 per cent of what one can say about the economic consequences of rent control. All of it was said, to be sure, repeatedly in the council chambers, but the discussion of the policy occupied but a small portion of the debate. Most of it focused on a simple, symbolic theme. Tenants--usually pictured as long-time residents of Cambridge--were being thrown out of their homes by rapacious landlords grasping for the higher rents students and other transients could pay. Eviction lists, tales of widows and amputees, and even skits were used to hammer at the theme.

It was a showdown in every sense of the word. Scuffles erupted in the council corridors between opponents and supporters of rent control. Women wept. Men cursed. Some women cursed. When the council, for the second time, voted down the convention's bill, for its supporters it was as if the guys in the black hats had shotgunned the guys in the white hats and had then ridden off into the sunset.

Why did rent control--a complicated, ambiguous policy issue--come to have such a symbolic significance for those who packed the council chambers?

In part, the answer lies in the fact that this is a time of troubles for Cambridge. Long established neighborhoods--cohesive communities with churches, bars, and candy stores all their own--are being threatened by a host of outside forces--the proposed Inner Belt highway, the new NASA center, and above all, an influx of new, would-be residents who are soaking up housing and driving up rents. People do literally get thrown out of their homes in Cambridge though, it must be admitted, how many do is not known.

FACED WITH these threats, many of the older residents of Cambridge have been looking for a solution or, perhaps more accurately, a panacea. Rent control on its face appeared to offer it: an insurance that one could stay the rest of one's days in the familial apartment, free from worries about rent increases. No matter that a rent control bill, any rent control bill, can't provide complete protection against rent raises, that it won't stop, the Inner Belt, or that it may even be impossible for Cambridge to pass a rent control ordinance without a specific enabling act from the state legislature--rent control seemed to offer the answer, a direct and personal assurance of safety in a time of peril.

Undoubtedly, this is how the bulk of the "little people" who filled City Hall felt, and this is why they found it impossible to react with anything other than anger to any action which appeared to hurt the chances for rent control.

Moreover, leaders of the housing convention--formed last September by the CEOC, the local anti-poverty agency--could not, even if they wanted to, which most probably didn't-moderate these emotions. The housing convention had lapsed into a period of inactivity after its formation and initial pleas to the City government, the universities and everyone else to "do something" about housing. The ferment over rent control revived the organization evaporate, as its supporters would drift instead to the Cambridge Rent Control Referendum, the radical group pushing for rent control.

Thus, the appeal of rent control as an issue--and the need to keep the housing convention going--made it likely that many a sign would be waved and many a voice would be raised on the issue. Yet more general factors--the style of Cambridge politics and the idea behind the agitation over the specific issue of rent control--were also at work.

The City Council has always been the focal point or at least the chief arena of politics in Cambridge, yet it is a body which possesses relatively little power. The City Manager has far more. Under the City's proportional representation system of elections, city councillors get to be city councillors by appealing, each to his own, to small, well defined groups of voters who usually live in one specific area of the City. Given their lack of power, city councillors try to satisfy "their people" in small ways--for example by getting them a traffic light--and by emotion-charged appeals with few implications for concrete action.

USUALLY REGARDED as the chief foe of the universities, Councillor Alfred E. Vellucci makes frequent speeches urging that Harvard and M.I.T. be, in effect, thrown out of Cambridge to some other place, say Waltham. Vellucci doesn't have the slightest chance of doing this, of course, and might not even want to, but his advocacy of such action strikes responsive chords in his East Cambridge supporters. Even in normal times, which these are not, politics in the City are apt to be heavily charged with rhetoric; the passions inherent in the rent control issue were amplified by this political style.

Packed council chambers are always likely to spark symbolic confrontations, and the chambers were very packed indeed during the rent control debate. In large part, this was due to the idea behind the entire housing convention movement, an idea currently popular with Federal agencies in Cambridge and elsewhere--"citizen participation." The young CEOC staff members who, behind the scenes, did much of the housing convention organizing take "citizen participation" in local government as one of their guiding lights and speared no pains to assure a large turnout of angry citizens for the council meeting and housing convention rallies. Get out a large number who feel strongly about rent control, tell them that they should speak up, and you're almost certain to have a major confrontation on the issue.