Although Obama didn't approve the Keystone expansion during his first term, most suspect that was a sop to his environmental base, who oppose the pipeline largely because they don't want Canada's carbon-heavy oil sands developed.

But not wanting to pass up the nearby crude, analysts expect Obama would approve the Keystone project during a second term, albeit with a strict environmental review and permitting conditions.

Romney has said he would approve the pipeline his first day on the job.

NEXT: Speculators