To introduce a (hopefully) less political data point, I find the way Apple's "I'm a Mac, I'm a PC" ads skirt the underdog issue to be fascinating.

Hodgman's PC is strongly cast as the underdog. It is, of course, the point of the ads that PC comes out the worse in every encounter, but what interests me is that we are clearly supposed to pity him, even to love him. Hodgman, bespectacled, round-faced, slightly pudgy, fits the part perfectly. We basically want to give him a big hug. Long's Mac seems reluctant to make himself appear too superior to PC, constantly afraid that he'll hurt his fragile feelings somehow. The ads give the appearance of trying to be as kind to PC as possible.

And yet, when we go to buy a computer, however much we may have sympathized with PC, we choose to ally ourselves with Long over Hodgman (or at least, so Apple hopes, and I assume they would not have paid to run the ads for three years had the effects been otherwise)