From the The Liberal Debating Manual (San Francisco: PeeCee Publishers, 2010):

No matter what position your conservative opponent takes on any issue, choose one or more epithets from the following list and label him with it:

Racist, bigot, fascist, sexist, intolerant, homophobic, Islamophobic, xenophobic.

Mix and match, and repeat as necessary.  Never ever engage conservative arguments.  To do so is to admit that your enemy is a rational being with a point of view worth considering.  Never credit a conservative with reason, moral decency or intellectual insight.  The smear is extremely effective if repeated often enough.   Never miss an opportunity to play the race card.  Insult and demean.  Tea-Partiers are 'teabaggers.'  If they reply in kind, act shocked and insist on the double-standard: we are morally and intellectually superior people while you are scum.  How can you object when we call you what you are: bigots, racists, scumbags?

Keep your eye on the prize and never forget that winning is all that counts.  The end justifies the means.  Example here.