Energy Secretary Steven Chu is a scientist and a scholar. He surely knows the effects of production of tar sands oil on climate change. He knows that it takes a massive amount of energy to do the strip mining necessary to extract tar sands oil. He knows about the potential for environmental damage from a 1,700-mile pipeline to distribute that tar sands oil from the source in Alberta, Canada to refineries in Texas. He’s a smart man.

He happens to work for an Administration that supports the tar sands pipeline, however. He’s a cabinet secretary and a team player. So he has to say things like this:

Chu, in a sit-down interview on Tuesday with the television program energyNOW!, did not say directly whether he supports approving the project, but touted its potential benefits.

Canada is a more stable supplier of oil than many other countries, Chu said.

“It’s certainly true that having Canada as a supplier of our oil is much more comforting than to have other countries supply our oil,” Chu said.

Chu also argued that technologies used to extract Canadian oil sands are “improving dramatically.”

“[T]he companies that are extracting these tar sands are making great strides in improving the environmental impact of the extraction of this oil and will continue to do so, and they should be encouraged and pressed to do so,” Chu said.

When you don’t really have a scientific argument (and the “great strides” companies are making on reducing the environmental impact of tar sands extraction still put them far above traditional oil drilling, which isn’t exactly clean), you have to go with the political argument. And so you get scientist Steven Chu saying that Canada’s a friendlier oil supplier than, say, Venezuela or Iran. Except the oil Canada will produce won’t go directly to the United States, but to the global market. It will be refined in Texas and sold wherever the demand is. So it doesn’t necessarily reduce US oil purchases from “scary” foreign nations; it merely goes into the mix of producers. This is a fallacious argument.

But I guess it’s the only one Chu has.

He did manage to call the Keystone XL pipeline a “trade-off,” so that’s something.