It's well-known that the United States consumes more oil per capita than any other country in the world, absorbing two-thirds of global oil production. This heavy dependence has often, and aptly, been described as an addiction; even U.S. President George W. Bush trotted out the metaphor in his 2006 State of the Union address ("America is addicted to oil").

Most of us regard addictions (to anything) as inherently unhealthy and admission of the problem as the first step toward getting clean. In this case, however, U.S. policy has simply been to seek increased oil imports from more reliable sources closer to home, in effect, to replace distant and unstable dealers with one from the neighborhood -- specifically, Canada, already the kingpin dealer of oil to the United States. In 2005 Canada exported almost 1.5 million barrels per day to the United States, about 7 percent of U.S. daily consumption. Canada exports 66 percent of its domestic crude oil production, and since 1995 the United States has received 99 percent of these exports. At first glance, it would seem that Canada wouldn't be able to boost oil production to fill the gap; production of conventional light and heavy oil in Canada was predicted to peak in 2006 and then rapidly decline. But that's where Canada's "unconventional" tar sands come in.