Palin has no responsibility to take over this, that's the whole point. Nobody on the right has any culpability for Loughner's actions, it never mattered if they found a stack of Tea Party literature in his lair or not. Whatever else Marx, Hitler, or Rand might have at their feet, his accolades of their works don't matter either. There's no responsibility to be taken by any of them, the modern rhetoric is incredibly light by historical standards and choosing one's word's carefully to never upset anyone crazy is ludicrous.