Canadian Prime Minister Justin Trudeau speaks during a Liberal Party caucus meeting in Ottawa last week. (Chris Wattie/Reuters)

The scandal was supposed to be squashed, story over, the damage done. But instead of closing the door on the political controversy that’s dogged his government for months, Canadian Prime Minister Justin Trudeau has thrown it back open, keeping the story in the news for another week.

For months now, the ordinarily prime-time-ready prime minister has struggled to stay ahead of allegations that his team inappropriately pressured the woman who was then Canada’s first indigenous attorney general, Jody Wilson-Raybould, to defer the prosecution of an engineering firm from Trudeau’s home province of Quebec.

The story seemed to culminate last week with the ouster of Wilson-Raybould and another high-profile, female ally from Trudeau’s Liberal Party, in what the National Post, a conservative newspaper, called the “Tuesday night massacre.”

Trudeau, in announcing the move, tried to cast it as a simple matter of party discipline: They were disloyal, they’ve been expelled, it’s time to move on.

Or not. On Sunday, Conservative Party Leader Andrew Scheer held a news conference to announce that he had received a letter from Trudeau’s lawyer threatening to sue him for comments he made about the controversy. In the letter, dated March 31, attorney Julian Porter said criticisms in a Scheer news release two days earlier had gone “beyond the pale of fair debate and is libellous” and warned of possible action under Ontario’s Libel and Slander Act, according to Canadian media.

The news conference gave Scheer a jump-start on the news cycle and a chance to grandstand on the issue of the day. He told the cameras that he stood by every criticism Porter mentioned. He said he would welcome the chance to hear Trudeau’s sworn testimony in court — an “I double dare you to sue me” response that evoked some sort of comical, Canadian political duel.

Trudeau is accused of pressuring Wilson-Raybould as attorney general to defer the prosecution of the Quebec engineering firm SNC-Lavalin and then demoting her to a lesser cabinet role when she resisted.

Canadian authorities charged SNC-Lavalin with paying bribes to secure business in Moammar Gaddafi’s Libya. If convicted, it could be barred from contracts with the Canadian government for 10 years. Under deferred prosecution, it could avoid a conviction by admitting wrongdoing, paying fines and committing to stricter compliance rules.

Wilson-Raybould told a parliamentary committee in February that Trudeau, top aides and government officials pressured her inappropriately to offer the company a deal. Last month, she released an audio recording of a telephone call with a senior Canadian official, angering Trudeau and his allies.

Those following the story from outside Canada might wonder whether this is normal — whether Canadian prime ministers tend to sue their political critics. It’s not unprecedented: Trudeau’s predecessor, Stephen Harper, once launched a multimillion-dollar libel suit against the Liberal Party after it published material alleging two Conservatives tried to bribe an independent member of Parliament. He eventually dropped the claim. Prime Minister Jean Chrétien once threatened to sue an opponent over allegations of bribery but never followed up.

Trudeau is certainly entitled to sue. But whatever the legal merits of his case, it’s hard to imagine how taking legal action against the leader of the opposition would help Trudeau move past SNC-Lavalin or put the focus back on his platform heading into on election in October.

In Ottawa, there’s speculation that the departure of Trudeau’s closest adviser, Gerald Butts, in the early days of the scandal has left the prime minister’s office short of sound, strategic advice.

Analysts have questioned, for instance, why a leader known for offering tearful apologies chose not to apologize for his treatment of Wilson-Raybould — a simple move that might have ended the issue right there.

Canadian pundits have for the most part been unsparing in their assessment of team Trudeau’s performance.

In an opinion piece published Sunday, Campbell Clark, chief political correspondent for the Globe and Mail, the country’s newspaper of record, wondered why Trudeau’s team lobbed a “slow pitch” for his political opponent to smash out of the park.

“The Liberal strategy to put the SNC-Lavalin affair behind them is going exactly according to plan,” he wrote. “Unfortunately for the Liberals, it is Conservative Leader Andrew Scheer’s plan.”

The response from the prime minister’s office has been to call out Scheer for focusing on SNC-Lavalin rather than on election issues, Clark wrote. The reality, he said, is that it’s Trudeau’s Liberals who “keep bringing it up.”

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Today’s coverage from Post correspondents around the world