His decision was one of scores of court rebukes to the Trump administration for decisions on the environment, immigration and transgender service in the military, among other issues, made hastily and, in the opinions of dozens of judges, without the "reasoned consideration" required by various federal laws, particularly the Administrative Procedure Act.
Morris wrote that the State Department had "simply discarded prior factual findings related to climate change" from the Obama administration in its zeal to further Trump's goal of letting the pipeline move forward. 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.
"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 it could take several months before the State Department is able to issue a new environmental impact statement, putting a timeline for a decision "well into 2019".
Western Canadian Select crude oil is selling at about $18 a barrel as its discount to USA benchmark West Texas Intermediate as a lack of pipeline capacity bottlenecks production in Alberta.
Becky Mitchell, chairwoman of the Northern Plains Resource Council, a plaintiff in the case, noted in a statement celebrating the ruling that the decision was "as good a ruling as we could have hoped for", as it "sends TransCanada back to the drawing board" on the pipeline's construction.
The pipeline construction sparked months of protests by Native Americans and activist groups, who say the project could pollute local water supplies. There's simply no excuse for approving this bad project.
The same environmental analysis that the department carried out before denying the permit in 2015 was ignored when the department turned around a year ago and approved it, the judge argued. "The department would have evaluated the spills in the 2014 [environmental review] had the information been available", Judge Morris wrote.
Morris' order does not permanently extinguish hopes Keystone XL will go ahead, but it will require the administration to come up with a better explanation as to why it should proceed.
Work can not proceed until the State Department completes a supplement to the environmental impact statement that complies with the National Environmental Policy Act and the Administrative Procedure Act, Morris ruled.
The construction of the Keystone XL pipeline has been stopped by a federal judge in Montana - at least until there's more environmental study on its impact.
A shortage of export pipeline space to carry away growing oil production in Alberta has been blamed for recent steep discounts in prices for Canadian oil as compared to New York-traded benchmark oil. "The only question is, how much longer is it until it is no longer needed?"