Wednesday's final Conservative leadership debate unfolded in the wake of entrepreneur Kevin O'Leary's shocking decision to withdraw from the race and endorse Maxime Bernier. The Quebec MP is now heavily favoured to become the next leader of the Conservative Party of Canada, unless the other candidates unite to stop him.

But instead they used the debate to once again promote their own agendas, while trying to diminish the new, clear front-runner.

"Max proposes simplistic solution for incredibly complex, fundamental issues, and we need more careful thought," Ontario MP Lisa Raitt maintained.

Story continues below advertisement

Read more: Kevin O'Leary drops out, endorses Maxime Bernier for Conservative leadership

Konrad Yakabuski: Is Maxime Bernier too principled to win Tory race?

Campbell Clark: Maxime Bernier stakes out controversial positions that challenge other Conservatives (for subscribers)

The key to winning is "not about who is going to impose a personal ideology that's going to divide our members and divide our caucus," said Regina MP Andrew Scheer, who maintained he was the only viable alternative to Mr. Bernier. Ontario MP Erin O'Toole then turned on Mr. Scheer, saying that in 2008 he "decided to leave the field of battle" to become House speaker in order "to hold receptions at the Kingsmere estate." That earned Mr. O'Toole boos from the audience.

Mr. Bernier's supporters should be feeling very good right now.

There are credible reasons not to hand the mantle of Leader of Her Majesty's Loyal Opposition, and the keys to Stornoway, to this former Quebec cabinet minister. This is not to say Mr. Bernier does not deserve to be leader. It is to say that party members and the other candidates should ask themselves a few questions, first.

Mr. Bernier was bounced from cabinet because he left sensitive documents with a former girlfriend who, it turned out, once had ties to organized crime. Does he have the judgment and good sense to lead the country?

Story continues below advertisement

Mr. Bernier is a true libertarian, something we have not seen in a leader before at the federal level. He attacks the equalization program, opposes all government subsidies to industry, would eviscerate the CBC and CRTC (which regulates telecommunications), wants to eliminate protections for the dairy and poultry industries, would privatize Canada Post and would withdraw the federal government from funding health care.

For a fiscal conservative, these are exciting policies. Maybe too exciting.

Mr. Bernier "has proposed policies that will lose the next election," Ontario MP Michael Chong maintained.

There is another reason to question whether Mr. Bernier is the best choice to lead the Conservative Party: He believes immigration policy "should not aim to forcibly change the cultural character and social fabric of Canada, as radical proponents of multiculturalism want." That message will not go down well in the immigrant-heavy urban ridings around Toronto and Vancouver where federal elections are decided.

You would think, in the face of such a suddenly powerful and powerfully libertarian leading candidate, others would rally to another standard-bearer. But that was not the case Wednesday night. Instead, Ontario MP Kellie Leitch repeated her pledge to require more careful screening of immigrants and refugees, which Ms. Raitt said tarred all Conservatives with the brush of intolerance "and I will not stand for that." Mr. Chong defended his proposed carbon tax, which all other candidates oppose. Several candidates insisted that their cuts to corporate and income taxes were more impressive than the others'. No, others insisted, mine are. All this for the thousandth time.

Maxime Bernier is an exciting candidate who offers fresh, original and bold – very bold – alternatives to the conventional assumptions on how Canada should be run. The party members may well decide that he is the best choice.

Story continues below advertisement

But the other candidates need to ask themselves whether they believe he is the best candidate for the party. If the answer is no, then the hard second question is: Who among them is best positioned to offer an alternative?

Party members will start receiving their ballots in the mail any day now. If a credible challenge to Mr. Bernier is to emerge, it must emerge within the next few days.

Otherwise, the leadership is probably his. Which may be a fine thing. We'll see.