Eric Simonson points out some great facts in a recent post equating the current day Kos to Hitler after WWI. Here's just a little smidget:
Fueled by bitter resentment and radical partisanship Kos sees not a political contest between opposing viewpoints but true mortal enemies to defeat at any cost. Fringe groups like the Nutroots need scapegoats on which to justifying their need for power. Thus the vast right-wing conspiracy is blamed for destroying the earth, creating poverty, treason, just about anything you can think of.
You can read the rest here.