The right for MPs to say and discuss almost anything they want is one of the central privileges of Parliament, but a couple of divisive debates over the past week tested the thresholds of dialogue in the House of Commons.

In one case, two spokespeople from the Canadian Immigration Forum were barred from speaking at the Commons immigration committee Wednesday because content on their website was deemed offensive -- including an interview with Canadian white supremacist Paul Fromm.

In the other, the NDP criticized Prime Minister Stephen Harper for allowing Conservative MP Stephen Woodworth to put forward Motion 312, a controversial proposal that sought to re-examine how Canadian law defines a human being.

The issue of restricting debate on abortion has come up before in other areas -- on Canadian campuses, for example. The pro-choice Canadian Civil Liberties Association has spoken out against barring pro-life advertising and activities at universities as a violation of free speech.

Liberal MP John McKay, visibly agitated Friday as he left another contentious question period, said the atmosphere after the vote on the motion earlier in the week was that of a funeral. McKay was one of four Liberals who voted in favour of the motion, which went down to defeat by a margin of 203-91.

"It kind of chills you; you don't really want to get into it and then you layer that over with the conflicts among colleagues, people with who you normally work," said McKay.

"The parallel that I would draw is to the capital punishment debate. At least there, the parliamentarians had the guts to deal with the issue and I think wisely dealt with the issue, but not us. We walked."

Witnesses ejected from committee

Madi Lussier, one of the two witnesses from the Canadian Immigration Forum not permitted to speak to the Commons committee, wiped away tears as she expressed her frustrations. The group's website is mostly an aggregator of articles on different issues touching on immigration, but divided into provocative sections with names such as "Chinafication" and "Arabization."

She has advocated a moratorium on immigration for 50 years, and warned that "European" values might be at risk of disappearing in Canada.

NDP MP Jinny Sims was the first to argue against the group appearing. She said there are certain lines that cannot be crossed when allowing groups to testify at committee hearings.

"Well, I think (the website) definitely reflects the views of a white supremacist," Sims said.

"We live in a diverse country, and a very inclusive country, and for a parliamentary committee to give due deference to both perspectives at an immigration committee, I think would not do this Parliament very proud."

Conservative MP Rick Dykstra, parliamentary secretary to the immigration minister, said that once the opposition began lumping his party in with the views of the witnesses, it became impossible to have a rational discussion about their testimony.

"Once you stir the dust up to the point you can't see anymore, you've got to clear the room, and I think it was the right decision to make," said Dykstra.

But Arthur Schafer, director of the Centre for Professional and Applied Ethics at the University of Manitoba, says it's disappointing that the committee did not allow the Canadian Immigration Forum to appear.

"Every point of view -- however ugly and obnoxious most Canadians might find it -- should be allowed to be aired in hearings before our parliamentarians," said Schafer.

"I think it's important, for example, that they understand the passionate racism that exists in some quarters in Canada and understand the reasons and justifications that such people give."

Schafer sees the abortion debate in a different light -- not as a free speech issue, but as a political one. Those who feel they shouldn't speak out -- or feel the wrath when they do, such as Status of Women Minister Rona Ambrose -- are simply experiencing the pressures of electoral politics.

David Eby of the B.C. Civil Liberties Association said he agrees.

"The motion was actually made, it was debated, and it raised the issue and duly elected parliamentarians voted against re-opening the issue," said Eby.

"It's not like it never showed up or was banned from being discussed by elected officials."