PMs and other leaders are NEVER involved in the detailed negotiations and only appear at the end to approve any last minute political decisions and to sign the ensuing agreement. Keystone XL might have got further if Harper hadn't told the Americans that it was a no brainer and he wouldn't take No for an answer. Nortern Gateway might have got further if Harper had tried to steer Enbridge away from the route and terminus that it had chosen. Now if Trump is going to put tariffs on Canadian goods entering the US, how does that jive with his statement that he would likely approve Keystone XL - what happens to the economics? Or is Trump just going to beat up on manufactured goods while sucking in resources as fast as possible?