"the dream of a nationally unified canada"

Because an older pipeline doesn't get repurposed, national unity is at risk?

The unifying aspect (had the pipeline proceeded) would have been the environmental risks shared by the four provinces crossed by the existing thin-walled pipe. 

By the way, I support the goal of self-sufficiency in oil supply and I'm not anti-pipeline. But EE was never the solution. Since the revival of Line 9 (which is even more thin-walled) much of eastern Canada's dependence on foreign oil has been reduced considerably. Consequently, most of EE's oil was destined for export, not domestic needs.