DEFECTION" and "Sell-Out" are words commonly heard in City Hall these days. The reason is simple: the traditional lines that divided Cambridge politicos into two camps, the independents and the liberals, have weakened this spring.

Animosities among city councilors have intensified and each city council meeting brings a new round of mudslinging.

After last year's election, the council looked like it would be a tight organization dominated by a five-man independent majority. The regime of former mayor Barbara Ackermann and her liberal Cambridge Civic Association (CCA) colleagues would be replaced by the likes of tough Alfred E. Vellucci and fast-talking Walter J. Sullivan.

But in January an unexpected battle for the mayoral post among the council's five independents led to the first major break within the group. After 30 ballots and a month of bickering, Walter Sullivan won the job, but not before making a classic political deal with the liberals.

Sullivan, who served as mayor for two years (1968-69) and who is the city's top vote-getter, solicited liberal support in his mayoral bid in return for support in his mayoral bid in return for support of the liberals' move to replace City Manager John H. Corcoran.

Corcoran was a friend of the independents, especially during the two years (1970-71) when the independents last controlled the council, during Alfred Vellucci's term as mayor.

Joining Sullivan in the deal with the liberals was freshman councilor Leonard J. Russell, who subsequently won the election for vice mayor.

Extremely angered by the outcome of the mayoral election, independent Thomas W. Danehy accused Sullivan and Russell of "selling-out to the CCA." Fellow independents Vellucci and Daniel J. Clinton were also upset but less vocal.

Danehy had campaigned for the mayor's office, arguing that he was next in line for the post. Sullivan and Vellucci were the last independent mayors. Councilors Clinton and Russell lacked enough council experience to claim the office, Danehy said in January.

Now Danehy remains bitter over Sullivan's affair with the liberals and has repeatedly tried to break up the romance with attacks on several fronts. He already has introduced a measure before the council to abolish the controversial rent control board in Cambridge. The three CCA councilors and Saundra Graham of the radical Grass Roots Organization defeated that measure with votes from Sullivan and Russell.

Danehy then tried to delay the appointment of Lowell City Manager James L. Sullivan as John Corcoran's successor at City Hall. To Danehy's amazement, Corcoran neither contested his dismissal nor called public hearings and the council majority followed through with Sullivan's appointment.

The city manager's salary then became an issue with which Danehy sharpened his attack on the council coalition. One the same March evening when the council voted to appoint James Sullivan city manager, the council raised the manager's annual pay from $34,000 to $45,000. Danehy called the pay hike "the most brazen political act ever taken in this city," and charged that the coalition raised the manager's salary prior to John Corcoran's April 1 retirement in order to increase Corcoran's pension.

Danehy also alleged that the council coalition had bargained with Corcoran, promising the pension increase, in return for his resignation without a fight.

"In order to get Mr. Corcoran to retire without having to fire him, the councilors told him they'd sweeten up his pay," Danehy said.

Independent Clinton, Danehy's closest friend on the council, said the raise "couldn't have come out of thin air. There must be some reason why a man who is about to be fired would not go through the usual hearings."

Clinton did not openly charge the council coalition with making an illegal political deal, but he was quick to point out that Corcoran was the first city manager in the history of Cambridge to be relieved of his duties without asking for a public hearing.

Danehy was more daring. At a council meeting he told a story of a woman who asked him about Corcoran's connection with the coalition. "She asked me if the councilors made a political bribe with Corcoran in order to pacify him," Danehy said.

Danehy avoided charging "bribery" himself, and repeatedly said it was only the woman who had suggested political bribery.

His comments irked his fellow independents. Russell said no deals were made with Corcoran and warned that if Danehy "mentions this again, I will take him to Third District Court."

The council coalition raised the manager's salary to $45,000 ostensibly to bring the city executive's salary up to par with salaries elsewhere in the state. But Mayor Sullivan revealed later that James Sullivan had stipulated that he would come to Cambridge only in return for a $50,000 salary. "We had to compromise to get Jim Sullivan," said the mayor, who is not related to the city manager.

War between the independents ensued during the first week of James Sullivan's term that began April 1. In his first order of business, Sullivan fired acting Budget Director Robert J. LeBlanc on the grounds that LeBlanc was too closely affiliated with Danehy and "could not be trusted to do a professional job."

LeBlanc reportedly served as Danehy's campaign manager in past elections and became a city official during Corcoran's administration. Danehy called LeBlanc's firing a "political move" and said LeBlanc is merely "a friend who votes for me."

Alfred Vellucci appears to have assumed the role of peacemaker in the last month by encouraging the independents to present a united front on such issues as the planned Kennedy Library and development of Kendall Square.

In late March Vellucci gathered the independents, including Danehy, to a pre-council meeting tea in the mayor's office. There he convinced his colleagues to draw up a resolution endorsing construction of the Kennedy Library in Harvard Square.

He brought a photographer to take pictures of the five independents together, holding a copy of the resolution. Danehy showed a weak smile while Vellucci joked and praised the independents for their ability to "get together for the benefit of the city."

At council meetings, Vellucci has become more critical of the liberals, especially councilor Ackermann, sniping at her and mocking her legal vocabulary.

Vellucci read a resolution to City Clerk Paul Healy in a recent meeting and was interrupted by Ackermann, who asked that Vellucci re-read sections of the resolution. He then spoke at an extremely slow pace. Ackermann interrupted again and said he did not have to be so deliberate in his reading. "I know you can't hear things well," Vellucci retorted. "So I'm going to re-read this so that even you can understand it. I know you're a little slow at these things."

Such exchanges, which are common now, enable Vellucci to refocus city council battles from within the independent group to the larger arena of independents and liberals. Yet Danehy persists in fighting Sullivan and Russell and he hampers Vellucci's efforts to mobilize an independent majority on the council.

The city council chamber has been an arena for colorful politicians for some time. Where Vellucci has been the traditional celebrity, Danehy is the rising star.

But in the battle for the spotlight, needless debate over procedures, politically-oriented resolutions and unnecessary exchanges of insults do the citizens of Cambridge no good. Perhaps Danehy's post-mayoral election anger will subside soon. Then the council can get down to the pressing business of running the city