HALIFAX -- Dalhousie University is facing scrutiny for investigating a student leader's polarizing social media comments as a group of law professors and a civil liberties group accuse the university of censoring political speech.

In a letter to the Halifax university senate, 25 law professors at Dalhousie's Schulich School of Law underscore what they call the fundamental importance of preserving a university community where political speech can flourish.

"While our constitutional order offers protection to many kinds of speech, none is more valued and protected than political speech," stated the letter sent Monday to Kevin Hewitt, chairman of the senate.

"Encouraging speech which challenges us as a community to reflect upon our roles in colonialism, oppression of marginalized communities, and systemic racism is critical to the mandate of this (or any other) university," the letter said. "Censoring such speech is antithetical to that mandate."

The letter asked the senate not to "police and censor" the tone of political speech.

Masuma Khan, a member of the student council executive, faced a backlash for urging the Dalhousie Student Union to abstain from Canada 150 celebrations in a show of solidarity with Indigenous Peoples.

In a Facebook post, the Nova Scotia Young Progressive Conservatives reacted by saying the student executive should help "instill pride in our country" rather than push for a boycott of a national holiday.

Khan, a fourth-year student, responded with profanity, questioning why she should be proud of colonization and "over 400 years of genocide," ending with a hashtag that criticized "white fragility."

Her comments prompted a formal complaint from another student alleging she discriminated against white people.

The university's senate discipline committee has agreed to hear the complaint. Khan had been a member of the committee, but says she has now been removed pending the outcome of her case.

The committee is expected to review the complaint against Khan in November or December.

On Sunday, the Ontario Civil Liberties Association accused the university of using its disciplinary powers to suppress political expression and freedom of speech.

In a letter to Dalhousie president Richard Florizone, the group called on the university to repeal its policies, which it says are inconsistent with Canada's core values of freedom of thought and expression.

"We believe that universities have no business interfering with the conduct of its students at such public off-campus venues," Joseph Hickey, executive director of the group, said in the letter.

"The legitimate desire for a functional learning environment ought not to be used as a smokescreen to stifle political debate and silence dissent."

The association said social media posts are a form of public speech in the so-called digital public square.

"They are off-campus activities as much as a debate in any public venue would be," the letter stated. "Dalhousie University must refrain from using the blunt tool of student discipline for indoctrinating students in what to think and feel, and instead must allow open and public debate on controversial matters."

Arig al Shaibah, Dalhousie's vice-provost of student affairs, said in a statement that the university's code of conduct allows students to raise concerns about behaviour they feel negatively impacts their learning environment and experience.

"With complaints of this nature, we engage in efforts to resolve issues through informal, educational and conversational means," she said last week. "If individuals involved are not agreeable to informal means to resolve matters, the code dictates that the matter must be referred to the senate discipline committee for a hearing."