Prime Minister Stephen Harper is defending the independence of the environmental review process underway for Enbridge's Northern Gateway pipeline, telling reporters in Vancouver the project will be evaluated scientifically and a green light to proceed would not be based on politics.

"Decisions on these kinds of projects are made through an independent evaluation conducted by scientists into the economic costs and risks that are associated with the project. And that's how we conduct our business," Harper said.

"The only way that governments can handle controversial projects of this manner is to ensure that things are evaluated on an independent basis scientifically and not simply on political criteria," the prime minister added.

On Friday, the federal government announced a firm deadline to ensure the joint review panel charged with evaluating the pipeline completes its work by the end of 2013, without further delays. But Harper's cabinet will have the final say on the project.

"The government does not pick and choose particular projects," Harper said, "the projects have to be evaluated on their own merits."

Enbridge's proposed pipeline, to move bitumen from Alberta's oilsands across B.C. to a new marine terminal in Kitimat, B.C., for export to Asia, has been identified by the Harper government as beneficial to its international trade strategy.

The prime minister reiterated his government's position that trade with the Asia-Pacific region is of "vital interest" to Canada and British Columbia, as the country's Asia-Pacific Gateway.

Harper also reminded reporters of investments in last spring's budget to bolster federal government inspection and monitoring for resource development projects such as this one.

Harper was in Vancouver Tuesday to announce a new type of employment insurance benefits for parents of seriously ill children.

Green Party Leader Elizabeth May described Harper's comments about relying on scientific criteria as an "about-face" and said it's the first time she's heard him say that when it comes to the proposed pipeline.

"I'm pleased to hear any sign of reason from the prime minister on this project," she told guest host Hannah Thibedeau on CBC News Network's Power & Politics.

Journalists in B.C. were keen to get questions to the prime minister after sharp criticism of Enbridge from the prime minister's senior cabinet minister for B.C., James Moore, last week. Harper did not contradict Moore directly, but appeared to offer a somewhat softened version of the government's previous position on the pipeline.

Reporters were kept well back from Harper and Moore on Monday when they attended Conservative Senator Gerry St. Germain's annual summer barbecue.

Public opinion set against pipeline

Harper's stops on the West Coast this week come at a challenging time for supporters of the pipeline.

Public opinion polls suggest the majority in B.C. is against the Northern Gateway pipeline project. Some First Nations along the route are determined to block it.

Enbridge's efforts to garner approval for the project have been set back by recent oil spills along other Enbridge pipelines, including damaging revelations about the way Enbridge handled its 2010 spill in Michigan.

Last spring's budget implementation bill streamlined the regulatory approval process for major natural resources development projects like Gateway. A firm deadline has now been set to ensure the joint review panel charged with evaluating the pipeline completes its work by the end of 2013, without further delays.

Cabinet will have the final say on the project. A statement from Natural Resources Minister Joe Oliver's office Friday continued to emphasize its potential to create jobs and economic growth.

But last Wednesday, Harper's senior minister in B.C. James Moore told a private radio program in Vancouver that Enbridge had put a "sour taste in the mouth" with its past actions and wasn't doing enough to win the confidence of British Columbians generally, and its First Nations specifically.

Moore said doubts about the Enbridge pipeline were "widespread" and repeatedly denied the Harper government would simply ram through approval for the pipeline, despite recent changes to streamline the approval process.

It was not immediately clear from Moore's remarks whether he was speaking only for himself as a senior minister representing the province's concerns, or whether his dressing down of Enbridge was an early signal of a still-evolving position from the federal government.

Premier wants concerns addressed

On Friday, B.C. Premier Christy Clark continued the stance she'd assumed during the premiers' Council of the Federation meetings in Halifax last month, saying that unless B.C.'s concerns were addressed the project would not go through.

"Alberta and the federal government have to come to the table with British Columbia to talk about making sure B.C. gets its fair share and to talk about how we're going to protect our environment to the best standards of the world," Clark said.

"Once they do that we can start talking about the issues. But if they don't do it, the pipeline will not happen," the premier vowed again.

B.C. has registered as an intervenor before the joint review panel. Clark has expressed concerns over B.C. not receiving enough financial benefits from the pipeline to correspond with the risks it would assume.

The prime minister said Tuesday he had spoken to Clark as well as other premiers about the pipeline, but his office confirmed that their most recent conversation was over the telephone prior to the premiers meeting in Halifax. No meeting with the premier was listed on the prime minister's publicly-released itinerary for this week's B.C. events.

"I am not going to obviously share with you any private conversations I have had with any premier," Harper told reporters. "I am not going to get into an argument or a discussion about how we divide hypothetical revenues."

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  • Top 5 Provincial Resource Spats

    Before the $5.5-billion Northern Gateway pipeline contract is even inked, not to mention approved by a federal panel, a heated quarrel has erupted between Alberta and British Columbia about divvying up the revenues.<br><br>It's not the first time in Canada that resources have spurred disputes between neighbouring provinces. And it likely won't be the last.<br><br>Here's a look at just a few examples of provincial spats, including the Alberta-B.C. one, over issues ranging from human to energy resources.<br><br> <em>With files from CBC</em>

  • Northern Gateway Pipeline

    Alberta vs. British Columbia<br><br>In the dispute over the proposed Enbridge pipeline, B.C. is calling for a share in the project's revenue to compensate it for the potential environmental risks inherent in running a crude oil pipeline across its land. Alberta has refused to share royalties, citing a province's right to income from natural resources within its own borders.<br><br>The proposal involves two pipelines, stretching a combined 1,177-kilometres, that would carry 525,000 barrels of oil per day from the Alberta oilsands to the ports on the West Coast. Enbridge has estimated that public benefits would amount to $2.6 billion in local, provincial and federal tax revenues over 30 years of operation. Environmental groups and aboriginal communities have opposed the proposed pipeline, particularly over worries of an oil spill.

  • Upper Churchill Falls Hydro Project

    Newfoundland vs. Quebec<br><br>Perhaps the most famous inter-provincial skirmish is the Upper Churchill Falls hydroelectric project. It's a battle that has raged between Quebec and Newfoundland and Labrador for more than half a century.<br><br>In 1969, Churchill Falls Labrador Corp. signed a deal with Hydro-Quebec that secured the creation of a power corridor through Quebec, enabling access to outside markets. In return, Newfoundland and Labrador agreed to sell a large portion of the electricity at a fixed rate until 2041 to Hydro-Quebec, the provincially owned utility.<br><br>The 65-year agreement did not account for inflation, nor the drastic rise in energy prices that was to come. Hydro-Quebec benefitted from the cheap price, profiting as it sold on the electricity to the U.S. and refused repeatedly to renegotiate the contract.<br><br>A 1996 report by Maclean's magazine found Newfoundland received $20 million a year by selling power to Hydro-Quebec, but the utility earned $800 million annually by selling that same power to hungry U.S. markets along the eastern seabord.<br><br>Since the 1970s, Newfoundland and Labrador has repeatedly tried to challenge the contract, seeking help from the federal government to the Supreme Court.

  • Construction Workers

    Ontario vs. Quebec<br><br>In the late 1970s, Ontario and Quebec began a tit-for-tat dispute over construction workers crossing the border to work in each other's province.<br><br>Dubbed the Ontario-Quebec Construction War in some newspaper accounts, the tiff appears to have started when Quebec enacted restrictions in 1978 effectively barring Ontario construction workers from certain projects there. Ontario sought to retaliate with similar rules. Thus began a political dispute that lasted decades, flare-ups often fuelled by economic downturns.<br><br>Quebec's highly-regulated construction industry has historically deterred Ontario workers wanting to work in Quebec -- while also driving Quebec workers into the more open Ontario.<br><br>Frustrated by the flow of workers into Ontario, Ontario enacted a Fairness is a Two-Way Street Act in 1999, barring Quebec construction workers from Ontario government projects. The two provinces eventually settled their differences in 2006 with a construction mobility agreement.

  • Timber Dispute

    Ontario vs. Manitoba<br><br>In Canada's early days, as boundaries were still being carved out, Ontario and Manitoba clashed for years over a tract of land on the western and northern boundaries of Ontario that each claimed as its own. An 1883 New York Times article described "frequent disgraceful conflicts" that "stopped short of bloodshed."<br><br>The tract was rich in timber and minerals, and also contained a port on Lake Superior.<br><br>In 1880, Manitoba extended its boundaries, with the federal government confirming them the next year.<br><br>But Ontario did not agree, saying the extension gave the disputed area to Manitoba. Confusion reigned in the disputed area as it lacked not only civil courts and a registry office to record deeds, but a timber agent to protect the forest. The U.K. judicial committee of the Privy Council finally weighed in. In 1889, the boundary of Ontario was extended west of Lake of the Woods and north to Albany River.

  • National Energy Program

    Alberta vs. Ottawa (and Ontario and Quebec)<br><br>In the wake of the energy crisis in the late-1970s, when the OPEC nations raised the price of oil, the Trudeau government introduced the National Energy Program, basically to equalize the price of oil in Canada and offset higher prices being paid the central and Atlantic provinces.<br><br>Highly unpopular in Western Canada, particularly in Alberta where most of Canada's oil is produced, the NEP sought to increase the federal share of energy revenues and make Canada a self-sufficient oil producer. Alberta viewed the program as an intrusion into provincial control over natural resources, as set out in the British North America Act, then the country's constitution.<br><br>Peter Lougheed, the Alberta premier at the time, retaliated against Ottawa by cutting provincial oil production. The fight caused huge uncertainty in the oil patch and essentially pitted the Western province against Eastern Canada. Lougheed said the federal government effectively "weighed Alberta's needs for markets against the economic advantages to Eastern Canada, and decided against us."<br><br>Eventually Lougheed and Trudeau signed a revised energy agreement in 1981, whch rejigged the revenue-sharing arrangement and reduced the NEP export tax on Alberta.<br><br>In 1982, the Supreme Court of Canada ruled Ottawa couldn't legally tax provincially owned oil and gas wells and the last vestiges of the controversial program were scrapped after Conservative Brian Mulroney was elected in 1984.