If you gave oil companies a choice between the tar sands in Canada or oil in Saudi Arabia, which do you think they'd choose?

There's no question that tar sands in Canada are probably the largest source of oil available to the U.S. over a long period of time. There's as much oil in the tar sands probably as there is in Saudi Arabia. The problem is, there's a huge capital requirement to develop that.

Extracting oil from the tar sands is a nasty, polluting, energy-intensive business.

There are two perspectives on the oil sands. You have companies that want to make it the next Saudi Arabia. The other is that it's a transitional resource to a low-carbon economy, and to regard it as anything else is to drain the continent's financial resources.

Saudi Arabia supplies much oil to the U.S. And it is the world's largest consumer of American weaponry.

The tar sands has changed Canada in the same way the fur trade has changed Canada.