I see the Middle Path not so much as the shortest route between here and there--of the kind laid out in a Google map--but rather as the navigational art of constant course correction. It's guided by an awareness of the changing environment, and of the distractions and obstacles we encounter along the way; it us leads forward not in a straight line but more of a zig-zag which allows for the unpredictable, the sudden steep incline, even the impassable.
The problem with principles is that we attach to them and attachment--I note with a nod of gratitude to the Buddha--leads to suffering. It also leads to intransigence, which by definition leads us nowhere. If we "stand on principle," we're immobilized by it. Is Buddhism itself not a system of principles? Not as I see it. It's rather an invitation to question every principle and put it to the reality test: does it work for me? Does it lead me and my fellow beings toward a greater common happiness? Or does it do the reverse?
The kind of course correction I have in mind would have to allow for compromise. It might even have to settle for the lesser of two evils. To take a particularly agonizing example, I think of Afghanistan. The choice is in essence a simple, binary one: to stay, or to leave. Beyond that, it's not so simple. If we stay, we are in the benighted violence-begets-violence bind. If we leave, we deliver millions of people into the hands of those who have already tortured them and promise to return to their medieval ways. We also risk opening the geo-political door to nuclear terrorism.
There is no easy or comfortable answer here, nor in many of the other urgent, infinitely complex problems that confront us. Those who would act on principle alone in the attempt to resolve them are, in my view, misguided. Important, yes, to hold our principles in mind as we navigate--but navigate we must. If we see an iceberg looming in our path--we should be so lucky perhaps, these days, as the polar cap melts!--it's time to swing the wheel.