It is no accident that the leading Democratic politician on Capitol Hill. Speaker of the House Thomas P. O'Neill, halls from Cambridge. Mass It is no accident either that he's a Democrat, because there essentially is no Republican party in the city (of the five state legislative races covering Cambridge last fall, only one was contested by a GOP candidate who got drubbed) And it is no mere whim of fate that he is a successful pol, because the city has a grand tradition of training aspiring officeholders with good old fashioned street corner, rough and tumble politics.

The two conditions may seem contradictory a lack of party rivalry and intense political battles But such apparent inconsistency permeates the Commonwealth Massachusetts is widely acknowledged as a liberal haven the only state which can boast of supporting George McGovern over Richard Nixon in the 1972 presidential race But from 1979 through 1982. It was ruled by Gov. Edward J King, who opposed abortion, supported the death penalty, condemned "welfare cheats," trumpeted the values of tax cuts and supply-side economics, and was embraced by President Reagan as his "favorite Democratic governor." King's reign came to an end after he barely lost the Democratic primary to the more liberal Michael S. Dukakis--who g sweet revenge for the 1978 Democratic primary when King unseated him. The explanation for the apparent inconsistencies lies in the realization that local conflicts--especially in this 350-year-old municipality--come as much from ethnic allegiance and personalities as from ideological convictions, and that even people who agree on their hatred for Ronald Reagan and defense spending increases can bitterly disagree over the issues closer to home.

Cambridge--with a population of 90,000--is divided into 10 neighborhoods, but with some rough generalizing, it can be broken down into five demographic regions. Harvard dominates mid-Cambridge, which blends in with West Cambridge as the upper-class academic, professional set. Northwest down Mass Ave lies North Cambridge, a heavily Irish Catholic region where the Speaker can be seen strolling the streets on an occasional Saturday afternoon. To the Northeast past MIT is East Cambridge--a tight-knit mix of Italians and Portuguese, with a recent influx of Haitians. The colorful, outspoken Al Vellucci, 36 years a city councilor and currently the mayor lives there And to the south lies Cambridgereport, once tapped as one of Lyndon Johnson's model cities, now a poor region with a high Black population. Saundra Graham, the only woman and the only Black on the city council comes from this region..

All these groups divide along two main political bloes. The city's high tenant populations joins hands with the white collar professionals the back the Cambridge Civic Association--a liberal coalition which, at age 40, is the nation's oldest municipal party. They are opposed by the more traditional ethnic and the landholders, who make up the Independents. Every add-numbered year is an election year (this being no exception) and at that time, the two groups fight over governing. The rest of the time they fight over issues. A brief explanation of both:

The Government

The city council is the discriminating body in the city. Every Monday at 5:30 p.m., the nine councillors convene and hash out matters ranging from the budget to street names. The members are elected at-large by the Hare proportional system: Cambridge is one of only a handful of American cities to use the scheme by which voters rank their preferences, and once a candidate gets a sufficient number of first place votes, his ballots spill over to the number two ranking candidate (or something like that). Currently, power is balanced, with the CCA and the Independents each holding four seats, and Vellucci, who calls himself a "small i" independent, often providing the swing vote.

The Mayor is elected by and from within the ranks of the councilors for a two-year term. The position is largely ceremonial, as the real chief executive of the government is the city manager, who runs the day-to-day operations of the government, and who has the power to hire and fire every city employee. The city's other elective body is the school committee, with seven elected members acting independently of the city manager.

The Issues

The issue dominating political debate in the is housing Cambridge has strict rent control and condominium conversion provisions, the result of a severe housing shortage that threatens to drive the city's traditional ethnic and blue collar residents to less expensive accomodations elsewhere. The five-member rent control board oversees the rent provisions. These statutes have come under constant fire from the Independents who have tried to modify the provisions.

Another issue which city leaders spend a lot of time on is nuclear arms. The city was among the first to reject the federal government's civil defense plans, and to support the nuclear freeze. A proposal on the November ballot would prevent any nuclear weapons research from being conducted in the city.

One perennial area of controversy is the relations of the city with its university neighbors. Both Harvard and MIT are large landholders, but are tax exempt. They each make in-lieu-of-tax payments for the services the city provides, but Cambridge officials complain that the figures are far below what the tax base could bring in. Another sore spot is Harvard's role as landlord. The largest landlord in the city, the University's relations with tenants are sometimes strained, and some city officials complain that Harvard is unwilling to discuss the matter.

Underlying these specifics, of course, is the tension natural whenever a mobile, fluid, upperclass, academic population mixes with implanted blue collar neighbors. Vellucci, who once called on the city to pave over Harvard Yard and make it into a parking lot, summed up the mentality best in a piece he wrote for The Crimson last spring: "Go into Macarelli's Bar in East Cambridge and ask the truck drivers and meat packers that drink there what they think of Harvard. They'll tell you that it gobbles up all the property in Cambridge and is populated with strange and eccentric people... Go back to Macarelli's Bar and...tell these good people that you will grant them any wish for their sons and daughters. They will all tell you the same thing; they wish that their son or daughter could be admitted to Harvard.