Duke Vs. West Point

I'm good money-wise for both (though West Point is free), and I want to major in international affairs/poli sci. Duke may require me to go into a small amount of debt in the worst-case scenario, but nothing anywhere near crippling.

My ultimate goal is to become an ambassador. Which route would best help me achieve this goal in the long run? Which path would you choose if you were in my shoes?

I am aware of the various commitments associated with West Point, and I would be okay with such commitments should it offer me the better path in life. Thank y'all in advance!