Den Tandt's pro-Keystone sentiments are standard issue, but his bit on Liberal strategy seems sound:
All of which leads us back to the Liberals: They oppose the Northern Gateway project, because it lacks local community support and because its proposed route envisions sending hundreds of oil tankers down the narrow and pristine Douglas Channel, in B.C. But they support Keystone, because it has passed every local environmental and national governmental hurdle, and because of its strategic importance to Canada’s economy.
On a symbolic level, that bifurcation bridges the gap between Tories and New Democrats. It makes the Liberals look like grownups, and the other two parties implicitly like ideological outriders. And it places the Grits squarely in the sweet spot of Canadian politics, which is the pragmatic centre, heading into the 2015 election.
I'd add a few other points as well. Keystone XL is probably the easiest pipeline to support because, well, any spills from it will wreck somebody else's country. And of course it is the decision over which Canadian's have least leverage, so there is not much credit or blame to take whichever way it goes. Note the LPC rationale, "lacking...community support", can be applied to Trans-Mountain or (Energy East) should the public relations ball get dropped there the way Enbridge did with Gateway. The LPC positioning here: supporting a pipeline to the West Coast in general but without getting behind any particular project seems similarly clever.