In 2015, the Obama administration rejected construction of the pipeline, saying it would detract from America's global leadership on issues related to climate change. That court previously has dealt his administration setbacks in its efforts to deport young immigrants brought illegally to the country as children, as well as its attempt to dismiss a lawsuit brought by 21 young people who argue the government must do more to combat climate change.
The Obama administration approved the southern leg of the pipeline that began operations in January 2014, easing a bottleneck between Cushing, Oklahoma, and refineries on Texas' Gulf Coast.
Trump claimed there would be "great construction jobs" stemming from Keystone XL, which involves the building of a 1,200 mile pipeline across six U.S. states in order to bring crude oil from Alberta in Canada to refineries on the Gulf Coast.
"An important dynamic here is whether the company remains committed to pursuing the project in light of ongoing regulatory delays, especially as we believe there is a strong desire to substantially complete the project before the next USA presidential election", Cox said.
He said the decision also fell short in other areas, including the impact on Native American lands, and did not take into proper consideration issues like oil spills and low prices.
TransCanada said in a statement to BNN Bloomberg that the company is reviewing the US judge's ruling on Keystone XL.
"This really underscored the painful year that Western Canadian producers are having and it's really a function of the lack of infrastructure", Rogers said of the ruling, which exacerbates Canada's pipeline pinch that has led to record-setting US$50-per barrel discounts for Canadian crude. There's simply no excuse for approving this awful project.
Construction of the U.S. leg had been scheduled to begin next year. "The department would have evaluated the spills in the 2014 [environmental review] had the information been available", Judge Morris wrote.
"It was a political decision made by a judge".
"It's emblematic of what we're seeing with the Trump administration, which is a very fast and sloppy reversal of prior decisions.in a way that doesn't adhere to the rule of law", Prange said.
Keystone XL roused a major environmental protest movement during Barack Obama's presidency, leading to arrests outside the White House and promises by activists to harass construction along the pipeline's route.
Asked how'd she react if the case ultimately wound up before the US Supreme Court, Carmen told host John Kiriakou that she doesn't exactly have a lot of faith in the highest court, "especially stacked as it is right now".
In August, Judge Morris ruled that the State Department must supplement a more thorough study of potential environmental effects of the pipeline. Opponents wanted to delay it until it was no longer needed as climate policies took hold.