He deftly shed the label of one of the most unpopular outgoing prime ministers in Canadian history, adopting instead the mantle of the wise, elder statesman. In the process, he caught a second wind in Tory politics.

But Mulroney's past just refused to stay in the old Tory closet, and ultimately Harper couldn't afford the liability. As he announced Friday that he would commission an independent probe into allegations of Mulroney's business dealings with controversial businessman Karlheinz Schreiber, Harper also severed ties with his former mentor.

"I think it will be incumbent on me and also upon members of the government not to have dealings with Mr. Mulroney until this issue is resolved," he told reporters.

That could be easier said than done.