OTTAWA - The Harper Conservatives have finally unleashed the attack dogs on Tom Mulcair.

They've pounced on the newly minted NDP leader's musings about the economic impact of Alberta's oilsands to paint him as a divisive, ill-informed, irresponsible enemy of western Canada who is unfit to govern.

But Mulcair isn't backing down. And he's fighting back.

He says the Tories are shirking their duty to protect the environment, allowing oil companies to pursue "unbridled" development and treat Canada as an "unlimited free dumping ground."

The third-party Liberals, meanwhile, are hoping to take advantage of the pitched, polarized battle to position themselves as the "voice of reason."

New Democrats had expected the Tories to go after Mulcair immediately after he was elected leader in late March, in much the same way they demolished the last two Liberal leaders, Stephane Dion and Michael Ignatieff, before they had time to make their own impression on voters.

Until now, however, the Tory attacks have been tepid, at best.

But the gloves finally came off Thursday as Conservatives trained sustained, heavy fire on Mulcair's assertion that booming energy exports, particularly from the oilsands, have created an artificially high dollar that has, in turn, hollowed out Canada's manufacturing sector — a phenomenon dubbed the "Dutch disease."

Canadian Heritage Minister James Moore, who represents a British Columbia riding, led the charge, backed up by a chorus of Tory backbenchers. Moore turned questions from the NDP leader on an unrelated matter into repeat attacks on Mulcair's fitness to be official Opposition leader, much less a future prime minister.

"I am wondering when the leader of the Opposition will apologize to western Canadians for suggesting the strength of the western Canadian economy is a disease on Canada," Moore told the House of Commons.

"He attacks western Canada, he attacks our energy industry, he attacks all of the West and the great work that is being done by western Canadians to contribute to Canada's national unity. He should be ashamed of himself," he thundered.

Moore warmed to his theme with each non-answer to Mulcair's questions.

"He should be ashamed of himself for attacking the West, dividing our country and not even having visited the places (the oilsands) he is attacking. It is unconscionable for someone who wants to be the prime minister of the country to be so utterly irresponsible."

If Mulcair was to actually visit the "the people whose economy he says is a disease in this country," Moore said he might at least "start the pathway back to a little dignity for the leader of the Opposition."

But Mulcair gave as good as he got. He countered that the root cause of the artificially high dollar is the federal government's refusal to enforce its own environmental protection legislation and make energy companies pay the costs of their own pollution.

"We are allowing these companies to use the air, the soil and the water as an unlimited free dumping ground," he said, accusing the Conservatives of using Nigeria, rather than the more progressive Norway, as their model for development.

"Their priority is the unbridled development of the oilsands. We stand for sustainable development in this country."

Mulcair later said the Tories had better think again if they think they can roll over him the way they did Dion and Ignatieff.

"As you can see as usual, when there is a substantive debate, all they can do is scream and try to bully you down. They've picked the wrong guy if they think they're going to bully me."

Interim Liberal leader Bob Rae expressed hope the fireworks may give Liberals a chance to do what they do best: come up the middle between polarized extremes.

"Well, I hope so. I mean I certainly like to be the voice of reason in all this," Rae told reporters.

Rae said Mulcair's "abstract economic theory" that resource development is to blame for the high dollar is "absurd" and questioned his political smarts in sticking to it so vigorously.

"When you're deep in a hole like Mr. Mulcair is, the first thing you do is stop digging. Instead of which, he just kept on digging deeper and deeper."

Rae suggested the oilsands issue has demonstrated that Mulcair does not have "a really deep appreciation of how sensitive these issues are in the national debate" or how proud westerners are that their energy-producing provinces are now the main drivers of Canada's economy.

"We do not gain anything as a country, in my view, from gainsaying their achievements. What we have to do is make sure they're sustainable. That's the key thing."

Loading Slideshow

• Syncrude Upgrader and Oil Sands

  The refining or upgrading of the tarry bitumen which lies under the oil sands consumes far more oil and energy than conventional oil and produces almost twice as much carbon. Each barrel of oil requires 3-5 barrels of fresh water from the neighboring Athabasca River. About 90% of this is returned as toxic tailings into the vast unlined tailings ponds that dot the landscape. Syncrude alone dumps 500,000 tons of toxic tailings into just one of their tailings ponds everyday.

• Boreal Forest and Coast Mountains / Atlin Lake, British Columbia | 2001

  This area, located in the extreme northwest of British Columbia, marks the western boundary of the Boreal region. On the border of the Yukon and Southeast Alaska, the western flank of these mountains descends into Alaska's Tongass Rainforest and British Columbia's Great Bear Rainforest. Far from the oil sands, the greatest remaining coastal temperate and marine ecosystem is imminently threatened by the proposal to build a 750-mile pipeline to pump 550,000 barrels per day of oil sands crude to the coast. Once there, it would be shipped through some of the most treacherous waters, virtually assuring an ecological disaster at some point in the future.

• Tailings Pond in Winter, Abstract #2 / Alberta Tar Sands | 2010

  Even in the extreme cold of the winter, the toxic tailings ponds do not freeze. On one particularly cold morning, the partially frozen tailings, sand, liquid tailings and oil residue, combined to produce abstractions that reminded me of a Jackson Pollock canvas.

• Aspen and Spruce | Northern Alberta | 2001

  Photographed in late autumn in softly falling snow, a solitary spruce is set against a sea of aspen. The Boreal Forest of northern Canada is perhaps the best and largest example of a largely intact forest ecosystem. Canada's Boreal Forest alone stores an amount of carbon equal to ten times the total annual global emissions from all fossil fuel consumption.

• Tar Sands at Night #1 | Alberta Oil Sands | 2010

  Twenty four hours a day the oil sands eats into the most carbon rich forest ecosystem on the planet. Storing almost twice as much carbon per hectare as tropical rainforests, the boreal forest is the planet's greatest terrestrial carbon storehouse. To the industry, these diverse and ecologically significant forests and wetlands are referred to as overburden, the forest to be stripped and the wetlands dredged and replaced by mines and tailings ponds so vast they can be seen from outer space.

• Dry Tailings #2 | Alberta Tar Sands | 2010

  In an effort to deal with the problem of tailings ponds, Suncor is experimenting with dry tailings technology. This has the potential to limit, or eliminate, the need for vast tailings ponds in the future and lessen this aspect of the oil sands' impact.

• Tailings Pond Abstract #2 | Alberta Tar Sands / 2010

  So large are the Alberta Tar Sands tailings ponds that they can be seen from space. It has been estimated by Natural Resources Canada that the industry to date has produced enough toxic waste to fill a canal 32 feet deep by 65 feet wide from Fort McMurray to Edmonton, and on to Ottawa, a distance of over 2,000 miles. In this image, the sky is reflected in the toxic and oily waste of a tailings pond.

• Confluence of Carcajou River and Mackenzie River | Mackenzie Valley, NWT | 2005

  The Caracajou River winds back and forth creating this oxbow of wetlands as it joins the Mackenzie flowing north to the Beaufort Sea. This region, almost entirely pristine, and the third largest watershed basin in the world, will be directly impacted by the proposed Mackenzie Valley National Gas Pipeline to fuel the energy needs of the Alberta Oil Sands mega-project.

• Black Cliff | Alberta Oil Sands | 2005

  Oil sands pit mining is done in benches or steps. These benches are each approximately 12-15 meters high. Giant shovels dig the oil sand and place it into heavy hauler trucks that range in size from 240 tons to the largest trucks, which have a 400-ton capacity.

• Oil Sands Upgrader in Winter| Alberta Oil Sands | 2010

  The Alberta oil sands are Canada's single largest source of carbon. They produce about as much annually as the nation of Denmark. The refining of the tar-like bitumen requires more water and uses almost twice as much energy as the production of conventional oil. Particularly visible in winter, vast plumes of toxic pollution fill the skies. The oil sands are so large they create their own weather systems.

• Boreal Forest and Wetland | Athabasca Delta Northern Alberta | 2010

  Located just 70 miles downstream from the Alberta oil sands, the Athabasca Delta is the world's largest freshwater delta. It lies at the convergence of North America's four major flyways and is a critical stopover for migrating waterfowl and considered one of the most globally significant wetlands. It is threatened both by the massive water consumption of the tar sands and its toxic tailings ponds.

• Tar Pit #3

  This network of roads reminded me of a claw or tentacles. It represents for me the way in which the tentacles of the tar sands reach out and wreak havoc and destruction. Proposed pipelines to American Midwest, Mackenzie Valley, and through the Great Bear Rainforest will bring new threats to these regions while the pipelines fuel new markets and ensure the proposed five fold expansion of the oil sands.