U.S. and Canadian statements regarding the decision on the Keystone XL oil pipeline may reflect a changing energy landscape in North America.

Industry supporters, and leaders whose economies depend in part on oil revenue, expressed frustration with the U.S. decision to deny TransCanada's permit to build the cross-border pipeline. But from the economic standpoint, many statements reflect evolving priorities in the new era for oil.

In its record of decision and national interest determination of the pipeline, the U.S. State Department, charged with vetting the project, said there were questions about the necessity for additional North American pipeline capacity given uncertainties about the future growth of Canadian oil sands production.

"Long-term trends that drive the investment decisions of oil-sands producers are difficult to predict," the State Department's decision read. "Since production remains uncertain post 2018, the corresponding amount of transportation infrastructure required also remains uncertain."

Keystone XL was designed to carry 830,000 barrels of oil per day from Canada to Nebraska. From there, it would eventually send oil through the so-called Gulf Coast Project, which TransCanada put into service in 2014, and on to refineries along the southern U.S. coast. The company said the entire network would've displaced crude oil from countries like Saudi Arabia, Venezuela and Iraq, crude oil that's more expensive per barrel and per shipment, than Canada's.

Lower crude oil prices in 2015 have crimped spending in the energy sector and starved economies like Canada's that depend heavily on oil for revenue. In terms of cost, the State Department said its analysis found most Canadian pipeline projects would break even with oil holding steady at between $65 and $75 per barrel, roughly 45 percent above the current price. A February review from the U.S. Environmental Protection Agency found assessments made on Keystone XL should be re-evaluated because crude oil prices are considerably lower than when the project was first envisioned.

Low oil prices created Canadian casualties most recently in October, when Royal Dutch Shell said it would no longer continue with the construction of its Carmon Creek project in Alberta and take a $2 billion write-down for the loss. The company attributed uncertainties in the Canadian crude oil market and the lack of export infrastructure for its decision.

Most of the crude oil Canada exports heads south into the U.S. market. For the week ending Oct. 30, U.S. federal data show Canada sent the United States about 2.7 million barrels of crude oil per day. That's a decrease from the previous week, but up 3.1 percent from 2014 and 21.2 percent from 2013 – increases that came with U.S. shale oil growth and without Keystone XL.

Compared with last year, Saudi and Venezuelan crude oil exports are down 27 percent and 39 percent, respectively.

Kevin Brin, director of the Canadian oil sands division at consultant firm IHS, said in response to email questions the United States still consumes more oil than it produces.

"Shale oil has primarily helped reduce U.S. reliance on offshore imports of light sweet crude oil of similar quality," he said. "U.S. heavy oil refiners face the prospect of continuing to rely on offshore heavy oil imports such as from Mexico, whose production is in historical decline, and Venezuela, which is also struggling and seeking to export elsewhere."

That fits with TransCanada's argument that a fundamental question for the pipeline was the origin of imports.

"Do Americans want to continue to import millions of barrels of oil every day from the Middle East and Venezuela, or do they want to get their oil from North Dakota and Canada through Keystone XL?" said TransCanada spokesman Mark Cooper.

For a Canadian economy struggling because of lower crude oil prices, officials expressed disappointment with the decision, but hinted at a changing narrative over North American energy policy. Alberta Premier Rachel Notley said she wasn't surprised by the U.S. decision, though she did express frustration with the characterization of Canadian crude oil as "dirtier," as President Barack Obama said.

Stephen Harper, whose Conservative Party was defeated in October's national election, made Keystone XL one of his top priorities during his administration. He argued the project was among the better alternatives, both economically and environmentally, to transport oil. Justin Trudeau, ushered to the Canadian leadership with October elections, said he supports Canada's energy-based economy, but would take a different position than Harper.

In response to the U.S. decision, Trudeau said bilateral relations hinge on more than Keystone XL, suggesting that, for Canadians, it was time for a new era of economic thinking.

"We know that Canadians want a government that they can trust to protect the environment and grow the economy," he said. "The government of Canada will work hand-in-hand with provinces, territories and like-minded countries to combat climate change, adapt to its impacts, and create the clean jobs of tomorrow."

U.S. and Canada share a strong economic relationship, which at more than $2 billion trade per day, was described by the State Department as "the biggest and the most consequential economic relationship in the world." Canada is showing signs of diversity, however. In September, Canada's trade deficit with countries other than the United States narrowed as a result of higher exports to countries like Turkey, Spain and India.

Exports of energy products, meanwhile, increased 3.7 percent to $5.2 billion in September.

Canadian officials said one of the pillars of economic success rests with bringing more oil to the global market. While the Keystone XL pipeline has generated the most media attention, other projects like TransCanada's Energy East project for the eastern market and Northern Gateway, an Asian-focused pipeline led by Enbridge, could expand market access beyond North America.

Analysis from consultant group Wood Mackenzie said the Keystone XL decision will not make or break Canada's oil sector. While Trudeau's administration is not seen as the strong energy advocate as his predecessor's, and while the situation beyond 2020 is uncertain, the group finds Canadian oil will still find its way to the U.S. Gulf Coast, especially if Canadian outlets to Asia remain locked in.

"We expect Canada's oil sands production to have market access between now and 2020 regardless of this decision," it said.