The nonsense goal of "energy independence" used to dominate the American political debate, and today with the rollout of his new energy policy Mitt Romney has tweaked it to a new level of nonsense in which the policy goal is "North American energy independence."
What's the difference? Well the difference is that the United States doesn't contain enough oil to meet our energy needs, so "energy independence" necessarily entails heavy reliance on renewables or nuclear both of which are low in greenhouse gas emissions. But Canada has lots of oil. So by tweaking the goal, you get to turn what was supposed to be a nonsense rhetorical wrapper for climate change policy into a nonsense rhetorical wrapper for promotion of oil and gas drilling.
But however you feel about Canada, nothing changes the fact that oil is a globally traded commodity. Even if we could fully supply ourselves with Mexican, American, and Canadian oil a huge war in the Persian Gulf would still create a huge spike in gasoline prices unless we could somehow prevent the export of North American oil to Europe and Asia. But unless you're planning to actually isolate North America from worldwide commodity markets, you're not "independent" of anything.
The actual issue at hand is climate change—should we limit CO2 emissions and subsidize research and deployment of clean technology, or should we just not worry about it and hope all the scientists are mistaken?