Former prime minister Brian Mulroney, seen testifying before the Commons ethics committee in 2007, has insisted he will remain a member of the Conservative party until he dies. (Fred Chartrand/Canadian Press)

A senior cabinet minister has pleaded with the president of the Conservative party to make peace with former prime minister Brian Mulroney — and been rebuffed, sources say.

Defence Minister Peter MacKay called the party boss last week and asked him to issue a public statement clarifying whether, as a former two-term prime minister, Mulroney could be a Conservative member for life.

That conversation with party president Don Plett was brief and unproductive — the Conservative Party of Canada does not offer lifetime memberships and would not make an exception for Mulroney.

Plett would not confirm the conversation, but he did not deny refusing such an entreaty.

"The Conservative Party of Canada has no lifetime members," Plett told The Canadian Press in an interview.

"The present prime minister is a paid-up member — and he paid for his membership, as did I and as did every other member in our party.

"In the past, Mr. Mulroney has been buying memberships. So obviously, at some point, somebody was aware that memberships needed to be purchased."

He said the Conservative party would "absolutely" continue to accept Mulroney as a member — provided that he ponies up the $35 for a five-year membership card.

MacKay a staunch Mulroney supporter

The response to MacKay's request illustrates the rift created last week when the party announced Mulroney had allowed his membership to lapse and was no longer a Tory.

Defence Minister Peter MacKay is a lifelong family friend of Brian Mulroney. (Canadian Press)

On one side of that divide are Mulroney's staunchest supporters — like MacKay, the last leader of the Progressive Conservative party and lifelong family friend of Mulroney.

Their appeals have failed to persuade the current prime minister or party brass that the membership rules should be bent to accommodate Mulroney.

"I don't want to comment on things that any minister has said," Plett said.

"But clearly, Mr. MacKay was part of the PC legacy party. I believe they had lifetime memberships. Whether this was a misunderstanding or not, I can't comment."

Sources confirmed the conversation took place Wednesday — the same day as a restless caucus meeting where Conservative MPs and senators bickered behind closed doors about Mulroney's treatment.

MacKay was preparing to leave for a NATO summit, where he was involved in a behind-the-scenes campaign to become the new head of the international military alliance.

Word leaked that Mulroney's membership expired

A spokesman for MacKay said he was still out of the country during this week's parliamentary break and was unavailable for comment.

Last Wednesday, the defence minister was in Ottawa and he was among those defending Mulroney. Plett was travelling in Halifax when he took the minister's call.

MPs had become restless after word leaked out to news organizations that Mulroney's membership had expired and he could no longer be called a card-carrying Conservative.

It was the latest move by party brass to distance themselves from Mulroney, just as an inquiry kicks off into his business relationship with arms-dealer Karlheinz Schreiber.

Some MPs immediately began calling the former prime minister to express their frustration, according to two sources.

A spokesman for Mulroney said the former prime minister received phone calls from at least a half-dozen MPs and cabinet ministers.

This occurred despite Prime Minister Stephen Harper's order for members of his government to sever ties with Mulroney until questions about his business dealings are cleared up.

"The thing that was surprising to me about the outpouring of sympathy and support in the last week was that it was in some measure from people who were in diapers when he was in government," Mulroney spokesman Robin Sears said, noting that some of the callers were young Ontarians.

"This was not simply his old friends rallying to his support. It was some much younger caucus members calling to say, 'I've always admired and respected you, sir, and I'm offended by what's been going on.' "

Sears said the calls came before and after the raucous meeting last Wednesday. Details from that caucus meeting were leaked to The Canadian Press in a rare act of defiance from a normally disciplined Tory caucus.