To quote Charles Dickens via the Simpsons: it was the best of times, it was the blurst of times. We’ve got our own tale of two cities in Canadian politics this week: in Toronto, the Progressive Conservative government rapidly brought emergency measures forward to the legislature, and the opposition — despite real and substantial reservations — worked quickly with the Tories to approve them. Meanwhile, in Ottawa, the first draft of the Liberals’ emergency COVID-19 response legislation was so irretrievably flawed that, when it arrived at Parliament Hill, MPs immediately suspended the House of Commons so that they could start from very nearly a blank sheet of paper.

The poison pill the federal government was trying to force the opposition to swallow: on top of the emergency-spending measures, the government wanted the power to lower or raise taxes, without a vote in the Commons, until the end of 2021. It was a direct attack on the powers of elected MPs, and they rightly insisted that the measures be deleted from the bill.

Parliament’s emergency measures — we really shouldn’t call them the government’s, given the full-scale rewrite — passed in the Commons early Wednesday morning with substantially expanded spending. The prospective power grab by cabinet ministers had been almost entirely rebuffed by opposition MPs.

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Liberals are going to hate to hear it, but they need to: Justin Trudeau and Doug Ford faced the same test this week, and the former was the one who failed badly. In truth, neither man should have to shoulder the full weight of either blame or credit — both first ministers have government house leaders to give them advice about managing relations with the opposition. Clearly, Paul Calandra (at Queen’s Park) has done a better job this week than Pablo Rodriguez (in Ottawa). But this was urgent legislation central to the recovery effort at both levels of government, and only one leader was able to stick the landing.

Trudeau’s defenders are already pointing to the fact that the federal Liberals are dealing with a minority Parliament, while Ford has a majority at Queen’s Park. But that context doesn’t really matter. The actual constraint on the kind of rapid passage of legislation we’ve seen this week isn’t a majority — it’s unanimous consent, meaning that if even a single MPP at the Ontario legislature had stood up and voted no, Ford’s policies would have bogged down just as surely as Trudeau’s did.

The recipe for speedy passage of emergency legislation is pretty simple: (1) put in a bill only the measures you absolutely need to execute your plan, and (2) put absolutely nothing in a bill that will force the opposition to say no.

It shouldn’t be necessary to add (3), but: Don’t try to eviscerate Canada’s parliamentary constitution.

Ford and his government adhered to these pretty simple rules, and they got their spending plan approved in record time. The New Democrats, led by Andrea Horwath, voted in favour of a budget for the first time since 2013, when then-premier Kathleen Wynne secured their support for a year.

It’s not that everyone at Queen’s Park is in love with the document the government unveiled on Wednesday. Indeed, every opposition party in the legislature presented substantial criticisms of finance minister Rod Phillips’s mini-budget: New Democratic, Liberal, and Green MPPs all insisted that the government wasn’t going far enough, fast enough — and, with the headlines we’re seeing daily, it’s hard to argue that they don’t have a point. But the government didn’t make them accept anything unacceptable as the price of moving forward, so everyone is agreeing to move forward for now.

For their sins, the federal Liberals may have caused some self-inflicted harm that will outlast this week’s headlines. The federal carbon tax, which will be defended again someday at the Supreme Court of Canada, also effectively delegated Parliament’s taxing powers (under Section 53 of the Constitution) to the federal minister of finance — which is exactly what the Liberals initially tried to do in this week’s legislation. There is some case law to support this kind of delegation, which explains both why the Liberals did it with the carbon tax and perhaps also why they thought they could get away with it this week.

But the lawyers for provinces attacking the federal carbon tax argued — well before this week’s events, well before COVID-19 was in the Canadian news — that giving those powers to the finance minister was too much and that, if courts continued to allow it, the government would eventually usurp that power and make the elected House of Commons irrelevant.

It was a hypothetical slippery-slope argument six months ago; after this week, it’s a fact in the historical record. Provinces on the anti-carbon-tax side will be able to point to the Liberal government’s efforts and say that, unless the Supreme Court of Canada strikes down the carbon tax and builds some new guardrails around Parliament’s Section 53 powers, some future government with a majority in the Commons will use the precedent to succeed where Trudeau failed this week.

The nine justices of the country’s highest court may or may not accept that argument. But it would be a historical own-goal if the carbon tax ended up being just another thing to die due to complications from COVID-19.