Tory leadership hopeful Erin O'Toole is steering clear of mudslinging in the race to replace Stephen Harper as head of the Conservative Party.

He's steering so far away in fact, that he has asked other candidates in the election to quit attacking one another and "remain united" in the months leading up to the final vote in May.

"It's tempting to succumb to personal attacks in an environment where the loudest and most outrageous statements win the most attention," said O'Toole in an open letter published Monday. "When we attack fellow Conservatives instead of debating policies, the only winners are Justin Trudeau, Rachel Notley and Kathleen Wynne."

Attacks aimed at Leitch and O'Leary

His comments come less than a week after fellow leadership contender Lisa Raitt held a press conference in Ottawa to publicly condemn the "irresponsible populism" of Ontario MP Kellie Leitch and celebrity businessman Kevin O'Leary, who is currently considering a leadership bid. Raitt launched a targeted new website called www.stopkevinoleary.com, and on Jan. 4 accused Leitch of wanting to "destroy one of the pillars" of Conservative success with her Trump-style, immigration-screening policies.

Raitt is not the only Tory in the race to lash out at a rival candidate. Veteran Conservative MP Deepal Obhrai called on Leitch last weekend to "stop her xenophobic attacks on immigrants" and accused her of "playing divisive and fear-oriented politics that can result in the Conservative Party becoming a rump protest party."

Obhrai tossed his hat into the ring in July last year, while Leitch launched her leadership campaign in October.

O'Toole, a former minister of veterans affairs under the Harper government, has encouraged candidates to make the leadership contest about debating ideas and policies, rather than attacking the party members who advance those ideas and policies. He vowed to refrain from personal attacks.

Lisa Raitt, Conservative Party of Canada, Ottawa, Canada
Tory MP Lisa Raitt, who hopes to replace Stephen Harper as leader of the Conservatives, fires shots at Kevin O'Leary and Kellie Leitch during a press conference in Ottawa on Wed. Jan. 4, 2017. Photo by Bea Vongdouangchanh

Race about "defeating Justin Trudeau's Liberals"

"Our membership deserves a vigorous debate of ideas," he said. "But I will not engage in personal attacks on fellow Conservatives... My friends, this race is about more than the leadership of the Conservative Party of Canada: it’s about the future of the conservative movement in Canada and defeating Justin Trudeau’s Liberals."

O'Toole was not available on Monday to answer questions about his letter over the phone, including whether his request for party unity could be perceived as an attempt to silence candidates who feel compelled to speak about controversial party issues. In a statement emailed to National Observer however, a member of his team, Melanie Paradis, clarified:

"Mr. O’Toole’s open letter today echoed what he has been hearing from countless Conservatives: let’s have a respectful debate about policies and ideas so that our members can elect the best leader, who can win the election in 2019 in order to put a stop to dangerous Liberal economic policies.

"The best way to debate ideas is to do exactly that, share your policies for debate. Many of the campaigns have not yet shared any policy ideas. Criticizing a fellow Conservative leadership candidate without offering up any policy ideas of your own, is not a debate."

Obhrai confronts O'Toole's letter

The campaign teams of Lisa Raitt and Kellie Leitch did not respond to requests for comment on this story, but in an interview, Obhrai said he will always stand up for his personal values, especially during a leadership debate. He said he didn't believe engaging the other candidates constitutes a break in party unity, but only serves to "enhance the debate."

“I went into this race because I have certain convictions, ideas and concerns," he told National Observer. "I will forcefully put forward my policies of what I think. Criticizing that other person by criticizing their policy is not insulting anybody. Mr. Erin O’Toole is welcome — if he doesn’t want to do anything, that’s his way of doing it. My way for 20 years is to stand up for what I believe in."

After the interview with National Observer, Obhrai sent a series of tweets to O'Toole confronting him about the letter.

Conservatives face a "strategic dilemma"

According to Frank Graves, president and founder of EKOS Research Associates, and a regular commentator on Canadian politics, the back-and-forth between Conservative candidates in the leadership race represents a "fundamental strategic dilemma." After reviewing O'Toole's letter, he said it's unclear which approach will be more successful.

"Do they try and exploit the wave of populism, nativism and xenophobia that is being produced by anger and fear about economic stagnation? Or do they try and re-establish a more moderate, right-of-centre conservative movement?" he wrote in an email statement. "The wild card here may be the ranked ballot, which could favour the less flamboyant and moderate approach. Yet the major new force in the political landscape seems to reward florid, know-nothingism. These forces are more muted, but nonetheless very much present in Canada."

While O'Toole's appeal for a debate on policies rather than "ad hominins and invective" is appealing, he suggested that it may be a bit optimistic in a post-Trump world that proves a no- holds-barred style of politics isn't going away.

There are currently 13 candidates in the race for Conservative leadership, with a vote scheduled for May 27.