The City of Cambridge may soon bring the state to court.

Last night, the Cambridge City Council instructed its lawyers to “prepare to take any and all legal actions” in response to the “obscene” Massachusetts House of Representatives’ redistricting plan.

The plan cuts Cambridge’s delegation in half, to just one full-time representative, and puts large chunks of the city into districts currently served by incumbents from Belmont, Boston, Arlington and Watertown.

“We owe it not only to the generations here today but the future generations [to take action],” said Councillor Michael A. Sullivan, who read the order to sue, which the council passed unanimously.

City sources rumored that Cambridge could sue on grounds that the redistricting violated the Voting Rights Act, because it broke up a district which for 25 years has elected a minority candidate.

But a successful suit on those grounds could be nearly impossible, because although the district has traditionally fielded a minority candidate, the district’s constituency is not primarily minority. The law requires proof of actual intent by districtors to break up minority neighborhoods.

“We’ve had extensive legal advice, and we obviously feel we have grounds for litigation,” said Mayor Anthony D. Gallucio, after a 50-minute closed executive session of the council with its lawyers.

Gallucio declined further comment, noting that the redistricting still has to pass through the Senate and get the governor’s signature before it’s official.

But since the legislation faces a Nov. 5 deadline, the city has just a few weeks to prepare its case.

“The law department is going straight ahead,” Gallucio said.

Although Cambridge has actually gained in population since the last redistricting, the Boston area population has declined relative to the rest of the state, and thus a seat had to be lost somewhere in the area.

The House plan, which passed late Monday night, cuts Cambridge into six pieces—previously it had been divided in three large chunks—and completely eliminates one of the city’s two current “full-time” representative seats, the traditionally minority 28th district seat currently held by Jarrett T. Barrios ’90.

“My district has grown in population such that had we maintained the same precinct lines it could say the same,” Barrios told the council.

An 11th hour amendment to the original redistricting cut the 28th district to prevent the merging of the districts of two incumbents from Newton.

Some blamed Barrios, who has all but announced that he will be running for a State Senate seat next year, for the fact that his district was cut.

“I am so angry at Representative Barrios,” said former state representative Sandra Graham, who held the 28th district seat from 1976-1988. “It probably would not have been on the chopping block if he had not let people know that he was running for State Senate.”

But in a joint statement, the current Representatives of Cambridge—Alice K. Wolf, Timothy Toomey and Barrios—stated that they “worked tirelessly to preserve our Cambridge districts.”

Wolf said that the decision to cut Barrios’s district violated two unofficial rules of districting.

“There are three tenets of redistricting,” Wolf said, which she enumerated as maintaining communities of “common interest,” maintaining “minority representation” and assuring that “incumbents don’t run against each other.”

“What has happened in the city of Cambridge is that the first two tenets were thrown aside for assisting the third in the city of Newton,” Wolf said.

Representative Paul Demakis—whose precinct gained a large chunk of Cambridge under the new redistricting—was the only member of the Cambridge delegation who voted in favor of the redistricting. Demakis also implied that Barrios was to blame for the drastic redistricting.

“Historically, the legislature has tended to focus on districts being vacated by the current representatives,” Paul Demakis said.

But Toomey, whose district is slightly more Somerville than Cambridge, disagreed.

“No individaul owns and representative seat in any part of the Commonwealth of Massachusetts—these belong to the citizens,” Toomey said.

—Staff writer Lauren R. Dorgan can be reached at dorgan@fas.harvard.edu.