Unless good sense intervenes, it looks increasingly likely that the State Department will approve the Keystone XL pipeline, which would carry a coarse, acidic crude oil from northern Alberta in Canada to refineries on the Gulf Coast of Texas. That would be a mistake.

In August, the State Department, which has authority because the pipeline crosses an international boundary, released its final environmental impact statement on the project. It found that the Keystone XL would have “no significant impact” on land and water resources along its route. We, and many others, are skeptical.

An existing pipeline carrying tar sands oil — owned by TransCanada, the Keystone XL’s operator — was forced to shut down for repairs after springing two leaks last May in North Dakota and Kansas. That is one reason why Dave Heineman, Nebraska’s Republican governor, has asked that the new pipeline be rerouted. He fears a spill could pollute the Ogallala Aquifer, a crucial water source beneath the Great Plains.

Unfortunately, the State Department appears to be more persuaded by proponents who claim that the pipeline will help reduce America’s dependence on oil from politically troubled sources in the Middle East. We are skeptical about that, too.