Ten months ago, I described 2014 as "decision time" for the Keystone XL pipeline. Now it looks like the change in political winds following the resounding Republican victory in the midterm elections will bring that decision closer. The bill may have narrowly failed in the Senate on Nov. 18, but Canadian Prime Minister Stephen Harper — Keystone XL's greatest champion — is about to gain some friends in Congress.

Even before the game-changer of the midterms, Harper was publicly buoyant about the prospects for approval of Keystone XL, a long-delayed 830,000-barrel-per-day pipeline to carry Canadian oil sands to U.S. Gulf Coast refineries. His priority was and is balancing the Canadian budget; he is relying on the project to get his oil exports moving, speaking of the "overwhelming economic case" for its approval.

But Harper's biggest obstacle so far has been the White House, which has been dragging its feet for six years delaying a decision one way or the other. In the meantime, Harper has been carefully wooing China in order to prove to his American counterpart that he has other options on the table. Most recently, Harper has been promoting the Energy East pipeline, which would shun the U.S. and take oil directly to Pacific coast terminals.

Starting in January, however, Harper will have more powerful friends in Congress — no one more so that Jim Inhofe (R-Okla.), who in January will become chairman of the Environment and Public Works Committee. Inhofe is one of a dying breed of climate skeptics and authored the book "The Greatest Hoax: How the Global Warming Conspiracy Threatens Your Future." He is just the kind of ally Harper, who has himself been accused of silencing climate scientists, needs on his side.

In the meantime, Barack Obama is steadying himself for a role as a "caretaker president." The next two years will be about protecting his legacy, a legacy he will have to fight to defend if he seeks to be remembered as a president who meaningfully recognized climate change and let environmental issues climb up the agenda.

But Obama will have a battle on his hands as his conservative opponents have lined up their targets. Along with rollbacks of the Affordable Care Act, energy looms large and the approval of Keystone XL is near the top of the list. Sen. Mitch McConnell (R-Ky.) campaigned on a platform that promised the oil industry Keystone approval in return for their support.

Faced with a hostile Congress, Obama is going to have to pick his fights. Keystone XL is a powerful symbolic issue for the environmental lobby and its celebrity backers, but some of their demands are unrealistic. When the pipeline approval bill inevitably passes through Congress and lands on Obama's desk, they want the president to aggressively use his executive power to veto it. Even then, there is a good chance the decision would be sent back to a Republican-dominated Congress and overturned.

What environmentalists must understand is that Obama has some bargaining to do. Keystone XL may be symbolically important but is not substantively at the heart of the environmental legacy the president is seeking to protect. He heeds Harper's hints at China as a willing alternative export destination. Obama also understands that creating an infrastructure bottleneck and hoping it will discourage Canadian oil sands production is no way to go about addressing global environmental challenges.

Ultimately, Obama's legacy will not be defined by noisy issues like this pipeline, but on quieter work being done on targets for carbon dioxide emissions from power plants, surprising gains in energy efficiency, a reinvigoration of the EPA and a promising expansion in renewables.

There have been disappointments — most notably flagship environmental policies such as the carbon cap-and-trade scheme that did not make it through Congress. But we cannot ignore that Obama has succeeded in positioning the U.S. as a key player in global initiatives to stem climate change, rather than the hindrance the country has become known for under his predecessors.

Most recently, the negotiations with China on carbon emissions hope to render futile opponents' arguments that "if China won't act, why should we?". The devil is in the detail of what is signed, of course, but on a political level the shift in perception is an important step.

After endless reviews, the route of the pipeline is currently under debate in a Nebraska court. A bill for its approval was passed by the House of Representatives, but its backers came out one vote down in the Senate.

Obama told a crowd at Georgetown University last year that Keystone XL will only be built if it is in "the national interest" and will not "significantly exacerbate the problem of carbon pollution." That leaves plenty room for interpretation of what that "national interest" is. He has also said in the past that climate change "is a challenge that does not pause for partisan gridlock." But in chess terms, when it comes to Keystone he may have to sacrifice a pawn to save his queen.

The President entered the White House on a wave of expectations in 2009. He is now entering a new era of compromise in which Harper and Keystone XL look likely to benefit. A yes or no on the pipeline is easy for U.S. citizens to grasp, but environmental progressives should not be disheartened by Keystone's likely approval early next year.

It would be a shame if we judge Obama's legacy on this issue rather than the more shrewd, if limited, wins on policies that build a more sustainable future for both the U.S. and global citizenry.