Story highlights Andrew Cohen: Canadian Prime Minister involved in a parliament fracas that has some questioning his maturity for job

Cohen: He apologized, but popular PM has lost his shine; has learned early lesson on governing, discipline, the scrutiny of celebrity

Andrew Cohen is a best-selling author and journalist who writes a nationally syndicated column for the Ottawa Citizen. His latest book is "Two Days in June: John F. Kennedy and the 48 Hours that Made History" (Signal/Random House). The opinions expressed in this commentary are solely those of the author.

Ottawa, Canada (CNN) What's going on with Justin Trudeau?

Since his surprising election last October, Trudeau has enjoyed soaring popularity as the young, hip, progressive Prime Minister of Canada. Blessed with charm, good looks, a name and a photogenic family, he has become an overnight international celebrity.

Promising "sunny ways" after a decade of the divisive politics of Stephen Harper and his Conservatives, Trudeau and his Liberals have proclaimed a new tone of civility in Parliament in their seven months in office.

Andrew Cohen

But all that dissolved on the floor of the House of Commons Wednesday in a fracas both unseemly and unprecedented. At the center was a less saintly Trudeau: petulant, impatient and later, embarrassed and "unreservedly" apologetic.

The contretemps was Trudeau's worst day in office. It raises questions about his maturity, and has given his critics, who have always attacked his youth and inexperience, reason to argue that he does not have the intellect or temperament for the job.

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