The New Democrats sent out a particularly tart news release on Tuesday to mock the Liberal government's climate policies.

"You. Bought. A. Pipeline," the NDP's campaign office wrote in what it described as a "reality check."

But that retort landed just hours after the NDP's own leader ably demonstrated just how difficult it can be to oversee resource development across a federation.

Appearing at an event in Winnipeg, Singh was asked by a reporter to account for his seeming willingness to let provinces veto interprovincial pipeline projects — an impression left by Singh's comments during an interview with CBC's Power & Politics.

Singh quickly insisted he was not promising a veto.

"No, no that's not correct," he said. "It's been reported that way but it's not what I said, ever. I never said that and I want to make it very clear."

So what is Singh actually promising?

The federal government has clear constitutional authority to approve interprovincial projects. Singh has acknowledged as much.

Who gets the veto?

But at that event in Winnipeg, Singh again said that he would not necessarily use that authority to pursue such a project if a province objected to it.

"I believe that the federal government has significant constitutional powers, but I don't think it's effective to impose pipelines on communities. It's not the way to go ahead," he said.

"And so what I said very clearly is I would not impose pipelines. What I believe in is working with provinces, working with Indigenous communities, in making sure we move forward in collaboration. We can't continue down the same path. It just doesn't work."

One province would be allowed a veto from a Singh government — Quebec, apparently because of its special status within Canada.

But the NDP would give no other province such clear authority to say no to an interprovincial project. At the same time, however, Singh wouldn't "impose" a pipeline on any province.

So what's the difference between a veto and not "imposing"?

According to the party, the distinction rests on Singh's willingness to work with provinces to allay concerns about a project, as opposed to simply taking no for an answer.

It's not clear that the distinction amounts to much of a difference. And it's not a purely hypothetical question. Consider the Trans Mountain pipeline expansion project.

Prime Minister Justin Trudeau tried to get B.C. Premier John Horgan to support the Trans Mountain expansion, and failed. (Darryl Dyck/Canadian Press)

In the fall of 2016, Justin Trudeau's cabinet approved the project, after satisfying the concerns of Christy Clark's government in British Columbia. But then Clark lost power and John Horgan became premier. And Horgan's NDP government was opposed to the Trans Mountain expansion.

Trudeau is said to have made some effort to appease Horgan. But Horgan's government persisted in trying to challenge the project.

Those challenges became the impetus for Kinder Morgan to halt spending on the project, a move that led to the Trudeau government purchasing the existing pipeline and the right to proceed with the expansion (the purchase that the NDP now mocks).

Would Singh have somehow convinced Horgan to stand down? That assumes there was anything any prime minister could have done to mollify the premier. It's just as likely that Horgan — whose New Democrat government depends on the support of Green MLAs for its survival — was never going to back down.

If Horgan couldn't be persuaded, would Singh have declined to approve the project? If so, would that not amount to a veto?

Pipelines if necessary — but not this one

In fact, Singh joined Horgan in opposing the Trans Mountain expansion. Awkwardly, the project pitted an NDP government in Alberta against an NDP government in British Columbia, with Singh ultimately choosing to side with the latter.

But in opposing the Trans Mountain expansion and the Liberal government's purchase of it, the federal New Democrats have sometimes sounded like their concerns extend beyond the project itself.

Singh has referred to "increasingly obsolete fossil fuel infrastructure." In June, the NDP leader suggested that Trudeau's stated commitment to combating climate change was contradicted by the prime minister's willingness to "approve a pipeline."

For that matter, mocking the purchase of "a pipeline" only makes sense if "a pipeline" is an inherently negative thing.

But the NDP is not categorically opposed to ever again approving a pipeline. The federal New Democrats have not yet found an actual project they could support, but they also have not yet ruled out the possibility. Indeed, there would be no need to worry about "imposing" a pipeline unless Singh was still open to such a thing being built.

Awkward questions

For the sake of making a clear break from the current government and courting anti-oil voters in British Columbia and other provinces, Singh might have been better off declaring that he would never approve another pipeline. The federal NDP is no longer encumbered by the presence of an NDP government in Alberta and the lone NDP MP in the province — Linda Duncan — is not seeking re-election.

But an outright refusal to support pipeline development would force Singh to answer other awkward questions — about the future of the oil industry and the people it employs, and about Western Canada's relationship with the rest of the country.

An unequivocal position against pipelines carrying oil also likely would revive questions about Singh's position on an emissions-producing liquefied natural gas project in northern British Columbia.

Singh has notably declined to clearly answer questions about that project. That proposal — a pipeline which would carry natural gas from Dawson Creek to Kitimat — is supported by the Horgan government.

"British Columbia's got one of the most ambitious climate change plans in North America," Singh told CBC's Power & Politics in May.

Of course, the same could have been said of Alberta under Rachel Notley's government.

In fairness, Singh would hardly be the first politician to struggle with trying to take an unequivocal position on resource development.

Six years ago, another leader of a third-place party said that "governments may be able to issue permits, but only communities can grant permission." Things proved to be entirely more complicated once that leader became prime minister.

If the past four years in federal politics have taught us anything, it's that resource issues make for complicated politics and difficult policy.

Singh and the NDP underlined that fact this week.