A City Council staff member, Viola Plummer, who vowed to end the political career of Council Member Leroy Comrie, even if it took “an assassination,” is being suspended without pay for six weeks and only will be allowed to return if she agrees to behave better in the future.

Plummer “made an incendiary and violent statement about a council member,” Speaker Christine Quinn said in a written statement yesterday. Her “behavior and subsequent comments were disgraceful and thoroughly unacceptable for a Council employee or anyone on the City’s payroll.”

Plummer will be required to sign a document agreeing to “conduct herself appropriately in the future and to cease being disruptive” at City Hall or in the course of her work as chief of staff to Council Member Charles Barron of Brooklyn, Ms. Quinn said.

She added that the council respects people’s right to free speech and expression, but said council employees acting in their official capacity do not have the right to threaten anyone or disrupt meetings.

In 2003, a political rival assassinated a council member, James Davis, at City Hall, a point noted by those outraged by Plummer’s remarks.

Mr. Barron said he will fight the decision in court.

“She has no jurisdiction over my staff,” he said. “She is going to be in for the battle of her political life.”

Ms. Quinn’s decision comes nearly one month after Plummer made the remarks outside City Hall after a heated council meeting during which Mr. Comrie abstained from supporting a proposal to rename a Brooklyn street after a black activist, Sonny Carson.

The renaming divided the council largely along racial lines with nearly all supporters of the new name hailing from the Black, Latino, and Asian Caucus. Mr. Comrie, a caucus member, is a close political ally of Ms. Quinn’s.

The speaker opposed the plan and said Carson, a convicted kidnapper who led racially charged protests, was a divisive figure with a history of making “anti-white” statements and did not deserve a spot on a city street sign.

Mr. Barron, a former Black Panther, was a leading proponent of the plan to name a street after Carson and said the late activist was a hero to him and to many black residents in Brooklyn.

A lawyer and former executive director of the New York Civil Liberties Union, Norman Siegel, said the suspension raises serious and substantial first amendment issues.

“To deprive someone of pay for six weeks based on their speech is, I think, constitutionally suspect,” he said.