Until recently, Justin Trudeau’s government in Canada was providing one bright spot for a Western centre-left which is, at least in English-speaking countries, rather embattled.

So it’s not surprising that the scandal currently engulfing the Liberal leader has been compared by one Guardian writer to “watching a unicorn get flattened by a truck”.

Whether or not this is actually the end of Trudeau remains to be seen – at the time of writing his party appears to be rallying round him. But even if he survives it will have indelibly tarnished his reputation as the great progressive hope, for the scandal itself undermines his credentials on several fronts at once.

At the root of the story are allegations that SNC-Lavalin, a major Canadian engineering firm, paid bribes worth tens of millions of Canadian dollars to the Gaddafi family in order to do business in Libya. If federal prosecutors successfully convict it on this charge it will face ten-year ban from bidding for federal contracts in Canada, potentially putting thousands of jobs at risk – especially in Trudeau’s own province of Quebec.

Mindful of this, and doubtless also the fact that he faces a general election in October, Trudeau tried to spare SNC-Lavalin a prosecution. But Jody Wilson-Raybould, his Attorney General, refused to countermand the federal prosecutors. So he demoted her, appointing her veterans minister.

What happened next appears to be Trudeau overplaying his hand. When the story initially leaked, via ‘anonymous sources’, Wilson-Raybould  refused to comment, not least because she was bound by attorney-client privilege. Taking advantage of this, he apparently tried to claim that she supported him, which prompted her to resign from the government.

A tactical resignation by one of the Prime Minister’s close advisers didn’t quiet the storm, and eventually Trudeau was pressured into part-waiving privilege in order to allow Wilson-Raybould to testify before the Canadian Commons’ justice committee… where she excoriated him. According to her testimony, the former attorney-general was subject to an extraordinary degree of pressure to make what looks like a politically-motivated intervention in the justice system.

For a politician with a brand like Trudeau’s, the story is poison. A professed feminist and anti-racist, he suddenly appears to have subjected a female Cabinet minister – and an Indigenous one, at that – to what looks a lot like professional bullying. A champion of ‘good government’, he’s now implicated in a grubby effort to shield a corrupt corporation.

The opposition Conservatives may not force his resignation now, but it can’t hurt their chances to enter the autumn elections against a badly damaged front-runner.