UNDATED — Quebec Premier Jean Charest had his moment — a pretext and a platform, as well as strong popular support, for a firm but fair crackdown on the violence and hooliganism that have wracked Quebec for weeks.

He appears to have squandered the opportunity, overplaying his hand with a vaguely worded emergency law that growing numbers of Quebecers believe was draconian and excessive. One consequence is the rest of Canada, which might have been spared a third round of national-unity wrangling — capping previous outings in 1980 and 1995 — is now back on track for more of the same, in 2014 or so.

Merci, Mr. Charest.

Evidence of the shift in sentiment emerged through the weekend on social media feeds emanating from Quebec City and Montreal.

A cursory read of Bill 78 reveals its architects made a bone-headed mistake: Rather than divide the opposition, isolating thugs and vandals from the mass of protesters, the law pushes them all together, and includes measures that appear to make it illegal to even encourage the striking students, or their representatives.

At a stroke, Charest increased the size of his opposition.

Saturday night on Montreal's Rue Saint Denis, for example, a restaurateur was arrested on his own premises, apparently because he had pinned a red square, emblematic of the protests, to his shirt. As I read Section 30 of Bill 78 — Anyone who helps or induces a person to commit an offence under this Act is guilty of the same offence and is liable to the fine . . . — the restaurateur, Dominique Dion, might be interpreted as guilty of breaking the law, simply because he'd welcomed protesters into his place. Even if untrue, that makes the law dangerously imprecise and open to abuse.

No surprise, every bright young lawyer in Quebec is now volunteering to work pro bono to help challenge Bill 78 in court, echoing a denunciation by the Quebec Bar Association.

Polls of ordinary Quebecers show public opinion, which has been firmly in the government camp for weeks, now breaking sharply in the other direction. A CROP poll taken Thursday evening and Friday morning, as the law was being debated in the Quebec legislature, found 66 per cent in favour and 34 per cent against. A second survey done over the weekend by Leger Marketing, after details of Bill 78 became known, showed support for the government plummeting, to 51 per cent, and student support rising, at 43 per cent.

A speedy return to peace, order and good government might have reinvigorated Charest's bid to prevent the Parti Quebecois, led by Pauline Marois, from re-taking power in the election that must be held next year, at the latest.

It might have shifted some attention, too, from the cascade of sensational headlines expected to emerge from the Charbonneau inquiry into corruption in Quebec's construction industry, which launched Tuesday. And that may yet happen. But given the events of the past five days, it is now far less likely.