A source close to what could be Peter MacKay's Conservative leadership campaign says the former Harper cabinet minister's decision on whether to run won't depend on what ex-Quebec premier Jean Charest does next.

While many Conservative insiders say they believe Charest will end up running for the federal Conservative leadership, a source close to Charest said he hasn't made a final decision yet.

Charest is expected to announce his plans over the next week. Some have speculated that, as leadership candidates, Charest and MacKay would end up drawing on the same potential base of support — which might make MacKay reluctant to join a race that has Charest in it.

That's not so, said a source in MacKay's camp. "Charest's decision has zero impact on (MacKay's)," the source told CBC News. "MacKay is doing a serious team building exercise. Winnability in Ontario and the East is key, that's the wheelhouse."

The source also pointed out that MacKay, who has a young family, "would be giving up a lot" by running. "Time with his three young children, a good job and his maximum earning years, but McKay believes the country is worth it."

Ambrose 'checks the boxes': Wall

Former Saskatchewan premier Brad Wall (whose name came up a lot in leadership speculation before he ruled himself out of the running last month) said he thinks Charest would be a good candidate — even though he personally urged former interim leader Rona Ambrose to run. Sources tell CBC News that Ambrose is expected to make her intentions known next week.

"I mean, Jean (Charest) was a national leader before. I actually supported him way back in '95, when he was unsuccessful in his campaign for the leadership of the PC Party against Kim Campbell," said Wall. "There's no doubting he's a great campaigner ... I think [he] still has great currency in his home province of Quebec, which is important."

Then-prime minister Stephen Harper and Rona Ambrose, minister of public works at the time, read to schoolchildren in Edmonton on October 8, 2010. (Dan Riedlhuber/Reuters)

Wall said he's not in a position to know whether Ambrose plans to run. "I think she knows where I stand on her potential candidacy," he said. "We haven't spoken since, I guess, a week or so just after the federal election. So it's been a long time since we've even chatted, other than me throwing her name around, maybe irresponsibly, in the media and social media.

"I think she checks the boxes, in terms of policy, in terms of electability ... and then finally, she's from Western Canada."

Western credibility

Wall said the next Conservative leader has to have a plausible plan for tackling the plight of the western energy economy and the political alienation in Alberta and Saskatchewan. He said Ottawa-area MP Pierre Poilievre's roots in the West might give him some credibility on that front.

"Well Pierre's dad is a Fransaskois," he said, referring to francophones living in Saskatchewan. "So there's some roots there now."

Poilievre is set to announce his candidacy soon. Former Harper minister John Baird is expected to be his campaign chair, and his team is expected to include 2011 and 2015 Conservative campaign chair Jenni Byrne. Poilievre did not respond to requests for comment from CBC News.

Erin O'Toole, left, and Pierre Poilievre make an announcement in Ottawa on May 12, 2015. (Sean Kilpatrick/The Canadian Press)

Ontario MP Erin O'Toole is expected to enter the race within days. The third-place finisher in the 2017 leadership race has assembled another campaign team. One member of his team told CBC News that O'Toole has been making calls "non-stop" to dozens of party organizers and members, and his 2020 team plans to put more emphasis on organization and the ground game than it did last time.

Meanwhile, a former communications officer in outgoing leader Andrew Scheer's office said he is "strongly" considering a run for the leadership.

In a statement released on Twitter, Rudy Husny said "Canadians want an authentic leader, with inclusive personal values and beliefs that represent the reality of a modern Canada in the 21st century, who won't re-open debates on established rights."

Husny is a Quebecer who ran as a Conservative riding candidate in 2011 and 2015, losing both times.

The only officially confirmed leadership candidate to date is veteran political organizer and businessman Bryan Brulotte. "My decision was taken after extensive consultation and encouragement from party members across Canada," Brulotte told CBC News in December.

The party is expected to outline the rules for the race on Saturday.

As CBC News reported last week, candidates will be required to submit a $300,000 fee and collect signatures from 3,000 party members to be on the ballot.

The name of the new Conservative leader will be announced at a convention in Toronto on June 27.