Natural Resources Minister Greg Rickford made the 11th-hour case in meetings in Washington with the U.S. State Department, his counterpart Ernest Moniz and pro-pipeline lawmakers.
He apparently received no guarantees, aside from a promise that the clock will start again on a regulatory process that had 18 days left when it was suspended last spring by a court dispute in Nebraska.
The Obama administration has given little indication that it's favourably disposed to Keystone XL, with the president routinely making disparaging comments about the project's lack of benefit to Americans and promising to veto Congress if it tries to force him to approve it.
In the face of all those apparent storm clouds, Rickford maintained an air of sunny optimism.
He said favourable U.S. public opinion, economic reality, and the environmental findings of a State Department report still have him feeling hopeful.
"As the eternal positive guy, I think this project is going to be approved at some point," Rickford said.
And on the off-chance that it isn't, he repeated a none-too-subtle political dig the Canadian government has begun reciting of late: polls have repeatedly shown Americans support the pipeline, Rickford told a news conference just down Pennsylvania Avenue from the White House.
"This is not a debate between Canada and the United States. It's a debate between the president and the American people, who are overwhelmingly supportive of this project," he said, reciting the new Canadian government line.
Rickford refused to be engaged in speculation about what would happen if Obama rejects the project, as many in Washington now expect he will.
He did say the Keystone uncertainty has left one clear lesson: the need to diversify Canada's export markets for energy beyond the U.S., which takes in nearly 100 per cent of Canadian oil and gas exports. He said he hopes to get more products to tidewater for export to new customers like China, Japan and Ukraine.
He also expressed hope that the Canada-U.S. relationship might soon move on to new challenges after more than a half-decade of Keystone discussion.
He did stress that he and Moniz made progress on other files during his two-day Washington visit, their fifth meeting in less than a year since Rickford entered his new post.
Over that period, the countries have signed a deal to co-operate more closely in 11 areas, such as data-sharing; negotiated a presidential permit for a hydro line from Quebec that would provide the equivalent of 10 per cent of New York City's power; and this week reached an agreement on nuclear energy.
The government says that deal would let Canada's heavy-water reactors use uranium from spent fuels from U.S. light-water reactors that are currently treated as waste. It also touches on co-operation in research and disaster preparedness.
Of course, the big bilateral issue hanging over the visit is Keystone XL.
Next week could see Congress pass, for the first time, a bill that explicitly approves the project — with Obama already vowing to veto it on constitutional grounds.
That sets the stage for a final decision by the president, which could come within weeks.
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