Sorry, I don't buy the broader appeal tning. It's nonexistent in the US. Stop chasing Republican votes and go after Democrats instead. How's that for a novel idea?
It comes with the territory of having the Electoral College elect Presidents.
You need to excite the progressive base in the US. Wareen can do that. Hillary couldn't. Maybe Democrats need to start chasing their own base before touting the backing of Henry Kissinger.
That assumes there is a large enough progressive base to win off. My understanding of the US is it is a fairly conservative country and a lot of Americans believe in American exceptionalism so anything that is seen as making the US more like Europe (or as a matter of fact Canada too) tends to be a tough sell.
Remind me again of what issues Stephen Harper and Andrew Scheer are to the left of even Ted Cruz on?