An example a common method of argument: Clinton believes in highway construction. Hitler believed in autobahn construction. Hitler is a Nazi. Therefore, Clinton is a Nazi.
This is guilt by association.
Not only is this a logical fallacy, it diverts the debate onto Hitler and Nazism. Also, it does violence to civilized discussion on FR, and makes further discussion unproductive in a thread.
Poor ol' Darwin is getting a really bad deal. It's not Darwin upon whom all the world's evils can be blamed, it's that arch-demon Thomas Edison! Think about it. Ever since he invented the electric light, and his evil followers have been using it -- polluting the divine darkness -- we've suffered communism, fascism, and a really sickening increase in teen pregnancy. And the public schools have fallen apart too. We must fight the evil of the electric light. Join me, freepers, in my holy and righteous cause!