This week America’s Senate is expected to debate the much-delayed Keystone XL pipeline, which would carry oil from Canada’s tar sands to refineries on the Gulf Coast. Several things have gone right for the project’s backers recently. Nebraska’s Supreme Court approved the proposed route, removing one obstacle. The House of Representatives passed yet another bill blessing Keystone last week, while the Senate’s energy committee voted to open debate on the floor. But because the pipeline crosses a border it also requires the approval of the State Department, which is in no rush to grant a permit that would infuriate environmentalists: greens regard the issue as a test of the White House’s good faith. Barack Obama has threatened to use his veto. Thus a political fight looms that is out of proportion to the importance of the pipeline itself. If oil remains at $50 a barrel, it might not be built anyway.​