BARACK OBAMA'S decision last year to put off a judgment on a proposed oil pipeline between Canada and Texas until after this year's presidential election swept a tricky problem under the carpet. Supporters pointed out that Keystone XL, a pipeline that would carry oil from Alberta's tar sands, as well as some from America's Bakken shale fields, would bring not just added energy security but jobs aplenty. Environmentalists would have none of these supposed advantages, decrying emissions-heavy oil from tar sands and claiming that in the event of a leak, the pipeline threatened a vulnerable aquifer on its route through Nebraska.

So the administration's announcement that it will now slap a big "rejected" stamp on the application from TransCanada, the Canadian company that wants to build and operate Keystone XL, seems to come down firmly on the side of the greens. But Mr Obama is still treading a fine line between the two sides. Thanks to resistance to the pipeline from Republican politicians in Nebraska last year, TransCanada had already offered to reroute it to avoid the Sandhills, a part of the state where the massive Ogallala aquifer rises almost to the surface. The ostensible reason for last year's delay was the need to study new routes (the unspoken ones being to duck a tough decision and placate the green lobby). The assumption was that the pipeline would eventually be approved in some form, but not at such an awkward time.

Republicans in Congress, however, tried to force the president's hand by inserting into an important spending bill a clause obliging him to rule one way or another by the end of February. The administration now claims, insouciantly, that it had to rule against the pipeline because the Republicans had denied it the chance to consider all the risks properly. In fact, little has changed. TransCanada can submit a new application for a similar pipeline following a new route, giving Mr Obama the respite he wanted while allowing him to bask in green adulation for now. The Republicans, for their part, can now make slightly stronger attack ads about Mr Obama's foot-dragging in the run-up to the election in November.

Meanwhile, the delays have strengthened Canadian resolve to find new ways of getting tar-sands oil to global markets. This might mean expanding an existing pipeline and building a new one to Canada's west coast for shipment to Asia's oil-thirsty markets. The western province of British Columbia, however, has feisty environmentalists of its own who might yet have a say.

The Chamber of Commerce is gnashing its teeth about the decision, but there are some American businesses who will rejoice at the new delay. The final section of the pipeline would have taken oil from Cushing, Oklahoma, to the Gulf coast, helping to alleviate a persistent price differential between Brent crude, the global benchmark oil, and West Texas Intermediate. Cushing, where most American oil is delivered is landlocked. There is not nearly enough pipeline capacity to the Gulf where global markets set prices. Unfortunately for American drivers, petrol (gasoline) is globally traded. The upshot is that local refiners can buy cheap Cushing crude and sell petrol at dearer global prices. So at least Mr Obama is keeping one lot of businessmen happy.