William Butler Yeats' observation still dead center on target nearly a century later:

Sarah Palin, Grassley, McConnell, Boehner, Rush Limbaugh, Glenn Beck, et al:

From The Second Coming:

The best lack all conviction, while the worst
Are full of passionate intensity.

Kind of says it all... right now it's the Republicans, but really, over time, it's the only bipartisan standard that's appropriate.