if you follow the logic in the statement he made last year about it being contingent on a state department review, the reality is that he has already approved the pipeline. and, in fact, it's already pumping. he's just waiting for the right political moment to announce it.
you have to understand that this is a national security issue. the oil is going to china. and, what does the united states focus it's entire foreign policy around? controlling the oil supply. this isn't an economic argument. environmentalists are trying to engage in a debate about the ecological problems, while correcting people on the economic value, but they're missing the point. from the government's perspective, it's not about this...
if canada doesn't ship it through the united states, it's going to be shipping it through british columbia, which is a national security problem because it's draining resources out of an area it considers it's backyard and towards a country it considers it's dominant rival. the military will not allow that to happen. the oil is going through the united states, and harper is going to be removed if he throws any wrenches into it. but, he's not actually throwing wrenches into it. the terms of conditions for the bc pipeline are going to take a decade to work out, the courts are going to slow it down, and by then the oil will be pumping from the south. so, harper can go to his chinese investors and say his hands are tied. it's no accident...
....because if they pump the oil through the united states, the military maintains control over it, including the ability to block export in the event of sanctions or war. this is what is going to happen whether anybody likes it or not.
it's also the reason canada is not allowed to build refineries, or airplanes or anything else. that would provide us with too much independence.
he'll probably announce it after the midterms, but he might wait as long as the end of his term, or even dump it off to a republican successor, if the politics allow for it.
http://www.youtube.com/watch?v=gVM2qOl144c