The city of Cambridge sent a legal complaint to several state officials yesterday, taking a major step in formalizing its impending lawsuit against the state, which challenges the legality of recent redistricting that eliminated the traditionally minority 28th representative district.

The city has signed on a major Washington law firm, Jenner and Block, to try its case—which it will pursue if and when the House redistricting plan passes through the Senate and is signed into law, according to Terrence F. Smith, the mayor’s chief of staff.

“The firm came up as one that had the experience we needed to file this sort of case,” Smith said.

Jenner and Block represents democrats in their redistricting battles nationwide, according to Assistant Professor of Law Heather K. Gerken.

“[Jenner and Block] specializes in redistricting,” said Gerken, who worked for the firm before coming to Harvard. “These guys are the best in the business.”

All of the city councillors have signed on as plaintiffs, except for Timothy P. Toomey, Jr., who also serves as a state representative. Saundra Graham, who said she was “the first minority to represent the seat” of the 28th district, has also joined the suit.

The suit could set a precedent on the extent of the Voting Rights Act, according to Gerken.

In its complaint, Cambridge lays out two claims about the redistricting. First, the suit asserts that the new districts “unduly fragment and divide the city of Cambridge”—and thus violate a state law which stipulates that neighborhoods must be kept together in redistricting.

The complaint also alleges that the Voting Rights Act was violated in the elimination of the 28th district “because the result will be to dilute the African-American and Hispanic voting strength in the Cambridge area, and statewide.”

This Voting Rights Act violation could be the suit’s stronger claim, according to Gerken.

“[The courts] are especially protective of the rights of racial minorities,” Gerken said.

But in Cambridge, a Voting Rights Act claim is unusual, because although the 28th district has traditionally elected minority representatives, its population is not a “majority minority.”

“The more conventional claim involves a majority minority district,” Gerken said. But no law limits the Voting Rights Act to protect only districts which have more than 51 percent minority residents, Gerken said.

“There’s a lot of debate right now about what constitutes a Voting Rights Act violation,” Gerken said.

This is a recent debate, according to Gerken.