Sixteen years ago, a handsome man in his 50s, who had been a big deal in the United Kingdom, addressed a Liberal policy convention. He was distinguished and impressive and he possessed the political allure that comes with having been a great success at something other than politics. Though he did not admit to having any ambitions for public office, he was already being touted as a potential successor to the prime minister of the day. Less than a year later, Michael Ignatieff was the Liberal MP for Etobicoke-Lakeshore. Four years after that, he was leader of the Liberal party. But the less said about what happened after that, the better. Mark Carney is not the exact facsimile of Ignatieff. A political turn by Carney — if he is so inclined — is not fated to end in tears. But Ignatieff’s story is a cautionary tale that Liberals, Carney boosters and Carney himself might want to heed before anyone gets too excited about the former bank governor’s appearance at this weekend’s Liberal convention.