Is it possibly due to your electoral system.  You are essentially a two party system, with a senate.  We have multiple parties running in our federal election. 

I believe there were 8 or 9 different parties on the ballot last month during our federal election.  I think this leads to less bi-polar fanaticism of the candidates.  Sort of like Baskins-Robbins, a flavour for everybody.  So you better be true to the people as we have a lot of choices in four years and you will be out on your ass.  Just speculation mind you...

ps Ed, it has been a hot muggy summer here, you can safely leave your bedroom window open as you sleep.  It will be alright, my wife and I leave ours open all the time.  But, you may choke when you see the price of gas here, 0.90$/ litre.  That is close to $4/gallon!