A Nebraska judge last week struck down a 2012 law that gave the state's governor the power to okay the Keystone XL pipeline that aims to bring tar sands oil from Canada to the Gulf of Mexico.
It was a Godsend ruling for Barack Obama, who now has months of breathing space before having to decide the fate of the highly controversial project.
To be clear, Judge Stephanie Stacy's decision pertained only to the state's constitution and specifically whether Republican governor Dave Heineman had over- stepped his authority. The ruling – stemming from a lawsuit filed by three farmers who opposed TransCanada Corporation's efforts to seize their land in order to build a 250-mile section of the 1,700-mile-long pipeline – will likely be appealed.
Major sections of the pipeline have already been built and brought online. But the section passing through Nebraska and South Dakota is fiercely opposed by many, because it would pass over the Ogallala Aquifer, which provides water for two million people in parts of eight states.
When campaigning for president in 2008, Obama declared: "It's time to end the tyranny of oil". But critics say he's done little to challenge Big Oil since then.
Obama raised the hackles of many environmentalists by green-lighting new oil exploration along America's Atlantic coast and parts of Alaska's Beaufort Sea in the Arctic. He's also an ardent booster of natural gas fracking, which, he claims, "has helped drive our carbon pollution to its lowest levels in nearly 20 years".
Some analysts predict that America will have surpassed Saudi Arabia in annual oil production by the time Obama leaves office in January 2017. Likewise, it's slated to pass Russia in combined oil and gas production during the same time period.
The Obama administration insists that it has been championing environmental issues. They cite the fact that 2009's $787bn (£472bn) economic stimulus package, which aimed to head of another Great Depression, included $90bn (£54bn) in subsidies for green industries. Since then, solar power output has increased six-fold, while wind power generation has doubled.
They also stress that US carbon emissions have been slashed by 12% since Obama took office and that the target cut of 17% by 2020 is within reach. And, next month, Obama is due to propose the creation of a $1bn (£600m) climate change fund in his 2015 budget.
All well and good, say critics. Keystone XL is another matter. The tar sands oil that TransCanada is producing in Alberta, which it wants to ship south across the US, requires huge energy outlays during the extraction process, virtually doubling its environmental impact.
If Obama's serious about fighting climate change, say critics, why not prove it by overturning the Keystone XL?
This being a congressional election year, Obama is loath to make a final call that would alienate voters on either side – be they supporters who'd be furious if he killed Keystone and its promised jobs, or environmentalists who'd accuse him of treachery if he approves it.
Judge Stacey's ruling likely means that he can delay that fateful decision until after November's elections.
But, no matter what other steps he may take on the environment, Barack Obama's environmental legacy will, more than likely, be defined by the Keystone XL's fate.