In the wake of last week's startling upset of Eric Cantor, it would be easy to believe that the political middle will once again be left out in the cold. Yet something unique is happening this primary season. Political moderates, the perennial underdogs of party primaries, the forgotten footnotes to the partisan favorites, are mobilizing. It's a trend across the country, seen not just in the Republican backlash against the tea party, but in independent candidates and unique, moderate Democrats.