The State Department today released its long-awaited environmental impact analysis of the Keystone XL pipeline. The analysis is key because President Obama announced last summer he would not approve the pipeline unless it was found to have no significant impact on climate change. And that’s what the analysis finds. It argues, as many other analysts have concluded, that if we block the pipeline, Canada will just ship the oil out by rail. So, what public policy reason is there to block the pipeline? There really isn’t one. Indeed, the environmentalists' obsession with Keystone began as a gigantic mistake. Two and...