MONTREAL—It was not for lack of being asked that Quebec premier François Legault declined to sign the letter five of his provincial counterparts and one territorial leader fired off at Prime Minister Justin Trudeau this week.

The letter warned of an impending unity crisis should Trudeau proceed with two environment-related bills. It bore the signature of every Conservative premier, from Ontario’s Doug Ford to New Brunswick’s Blaine Higgs and including Manitoba’s Brian Pallister, Saskatchewan’s Scott Moe and Alberta’s Jason Kenney.

Bill C-69 overhauls the rules that govern the approval of major resource projects. Bill C-48 would see tanker traffic banned off part of the B.C. coast. Both reflect Liberal election commitments. The Conservative premiers argue the combination will be seriously detrimental to Canada’s resource industry.

There is little the premiers would have liked more than to have Legault join them on the war path and they tried hard to recruit him.

As it happens, the Quebec premier is no fan of the updated regulatory regime Bill C-69 heralds. Like its Liberal predecessor, the CAQ government feels it infringes on the province’s constitutional powers. If it is challenged in court, Quebec will likely line up against it.

But there will be a federal election before any of that happens and, in no small part, that is why Legault is happier on the sidelines.

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The official reason for declining the invitation to sign was that the amendments the Conservative premiers were adamant Trudeau accept in the final version of bill C-69 did not reflect Quebec’s concerns.

But Legault was also wary of the partisan undertones of the letter.

The end game of the Conservative premiers is not to have a pair of environment-related federal bills dismissed or rewritten.

Their latest offensive is part of a battle to the finish to help Conservative Party Leader Andrew Scheer oust the Liberals from power in the Oct. 21 federal election.

Prime Minister Justin Trudeau and Conservative deputy leader Lisa Raitt trade jabs in question period about who is threatening national unity over energy projects – the Liberals, or six premiers, five representing conservative provincial governments and the sixth a territory. The premiers asked Trudeau in a letter to accept every one of the Senate's amendments to bill C-69.

That’s a fight-by-proxy Legault has no intention of being dragged into. That’s not only because Quebec voters remain ambivalent towards Scheer.

Legault knows first-hand the perils that await a premier who puts political capital on the line to defeat an incumbent prime minister.

He was a member of Lucien Bouchard’s Parti Québécois cabinet over the course of the Ottawa-Quebec battle over the post-referendum federal clarity act.

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At the time of the 2000 federal election PQ strategists were convinced then-prime minister Jean Chrétien would pay a hefty electoral price in Quebec for having given Ottawa the legal capacity to set the terms of engagements of future referendums.

They believed voters would rally to the premier’s contention — one shared by the bulk of the province’s chattering class — that the federal law was an attack on Quebecers’ collective right to self-determination. They hoped it would rekindle sovereigntist passions.

They were wrong. Chrétien won the popular vote and almost tied the Bloc Québécois for seats. A short time later, Bouchard resigned. He said the federal result was a major factor in his decision. The latter did suggest that in his role as Quebec gatekeeper vis-à-vis Ottawa, he was all bark and no bite.

Come the Oct. 21 vote, no one will be surprised if Alberta and Saskatchewan voters follow their respective premiers in the federal Conservative camp. A plurality of voters in each province never left the federal Conservative tent to begin with.

But whether Doug Ford — an unpopular Ontario premier whose vocal backing of Scheer the Liberals hope will drive more votes their way — or Higgs, whose New Brunswick government was elected with a smaller share of the popular vote than the official opposition, will be similarly vindicated by their respective electorates is much less certain.

Trudeau could yet replenish his moral authority at their expense, leaving them with a weaker hand in their dealings with a re-elected Liberal federal government and some egg on their faces on the provincial front.

If the litmus test of a prime minister’s success at keeping the federation in one piece rested on the quality of his or her relationships with the premiers, most of Trudeau’s predecessors would have failed it.

Chrétien consistently butted heads with the premiers of Quebec, Ontario and Alberta. Neither Bouchard, nor Mike Harris nor Ralph Klein were predisposed to play ball with a Liberal federal government.

Stephen Harper fought a number of provinces in court over his senate reform bid and his plan for a national securities regulator — and lost.

By comparison, Brian Mulroney was the hands-down champion at achieving consensus at the first ministers’ table. He secured the unanimous consent of the premiers to engage in a major reform of the Constitution not once but twice over a period of five years.

And yet no recent prime minister left the country quite as profoundly divided as he did.

It is worth noting that Mulroney came to office as determined to champion Quebec’s constitutional cause as prime minister as Scheer is today about championing Alberta and Saskatchewan’s energy ambitions.

Chantal Hébert is a columnist based in Ottawa covering politics. Follow her on Twitter: @ChantalHbert

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