Federal systems of government are splendid things: robust, flexible, able to accommodate conflicting local values. When it comes to the fight against global warming, federalism is the ace up Canada's sleeve, while south of the border it's America's last, best hope.
Conservative prime minister Stephen Harper was right to withdraw Canada from the Kyoto Protocol on climate change in 2011. The Chrétien government had made promises at Kyoto that no Canadian government could keep without wrecking the economy. The expanding oil sands in Alberta had become a major driver of growth. The U.S. Congress was blocking president Barack Obama's efforts to fight global warming.
Any Canadian tax on carbon without an equivalent American action would simply kill Canadian jobs, without lowering the planet's temperature even a smidgeon, Mr. Harper argued, and that argument made sense.
But, although Ottawa wasn't ready to fight climate change, some provincial governments thought differently. Quebec had a natural advantage, because most of its electricity is generated by hydro. The Liberal government in Ontario wanted to replace lost manufacturing jobs in traditional industries by developing green-energy technology. British Columbia premier Gordon Campbell believed that a carbon tax was the most business-friendly way to lower emissions.
When Rachel Notley's NDP came to power in Alberta, committed to bringing that province in line with others in the fight against climate change, Mr. Harper shrugged. Ottawa's job, he believed, was to get a pipeline to tidewater somehow, somewhere. If the provinces wanted to go all green, they were welcome to knock themselves out.
But then Mr. Harper was replaced by Justin Trudeau, and Mr. Obama by Donald Trump. The White House is now even more of a climate-change-denier than the House of Representatives or Senate, while the Liberal government is as enthusiastic about fighting climate change as any province.
In Canada's case, federalism worked to provide in advance what Ottawa now seeks: a national (if piecemeal) strategy to reduce carbon emissions through provincial cap-and-trade or carbon tax schemes, with only Saskatchewan's Brad Wall seriously offside.
In America's case, federalism and the entrepreneurial energy of the private sector have combined to limit the damage inflicted by Washington. About 30 states have green-energy strategies in place. Elon Musk resigned Thursday from two of Mr. Trump's advisory councils in protest over the President's decision to withdraw the United States from the Paris accord on climate change. Of course he resigned: His Tesla Model 3 electric car will soon hit the streets in an increasingly competitive electric vehicle market, going head-to-head with, among other competitors, the Chevy Bolt and the Volkswagen eGolf.
The battle in North America against global warming will be most successfully fought in dealer show rooms. Mr. Trump, with his Luddite refusal to recognize the transformation under way in his own country's economy, is making that battle harder to win, which is why dozens of mayors and CEOs vowed to continue efforts to reduce carbon dioxide emissions in the wake of the President's announcement.
Federations aren't perfect, as both Canadians and Americans know. Local turf wars can prevent unified action – just witness the years of effort, mostly futile, to eliminate internal barriers to trade in Canada.
And while the Trump White House is egregious in its foolishness on climate change (and so much else), the Trudeau Langevin Block has its own issues. Threatening to punish recalcitrant provinces with a federally imposed carbon tax is a mistake; in federal politics coercion is generally a mistake.
And if Washington has replaced the eagle with the ostrich (thank you, Bob Rae, for that tweet), Mr. Trudeau's green rhetoric fails to match his actions: The Liberal climate-reduction targets are essentially identical to the old Conservative climate-reduction targets.
Still, this is a good time to celebrate the diversity of federalism, which is working both to Canada's and America's advantage on the climate-change file.
Something to remember the next time we grind our teeth at the unwieldiness of federalism. Unwieldy is good. It limits the damage of stupid.