One common (folk) etymology given is that it originated with men who stood outside of courthouses with a straw in their shoe in order to indicate their willingness to be a false witness. Another is that a man made of straw, such as those used in military training, is easy to attack. Attacking a straw man can give the illusion of a strong attack or good argument.For my money, the second account makes more sense, and certainly matches the metaphor.
Democrat apparatchiks, Obama sycophants, and leftists of various stripes are using the straw man argument of "racist intent" against an astonishing number of those who dissent with any of our president's policies. They are, to mix metaphors, playing the race card with abandon. The range of people engaging in the practice is staggering: from New York Times columnists (Maureen Dowd), to rock music stars (Dave Matthews), to tattooed comedian/actors (Janeane Garofalo) to an ex-president of the United States (Jimmy Carter).
The beauty of this tactic is, a) like a joker, it's a wild card that can work for all occasions, and, b) it leaves your opponent stupefied. Let me take these points one at a time.
a) The race card works for all occasions.
The race card has been used against large groups (the "tea parties," the vast numbers of seniors who have protested against Obamacare, the Republican party as a whole) and individuals (Joe Wilson). It works regardless of what your opponent says because a "secret" or "hidden" or "unspoken" intent is attributed.
b) It leaves your opponent stupefied.
The use of the race card is like the old vaudevillian question, "when did you stop beating your wife?" Any reply seems self-incriminating. If one gets angry at the accusation, one's very anger will be used as an indication of his guilt. The "some of my best friends are..." response will solicit rolling eyes or derisive laughter. And silence will be seen as consent.
An additional benefit to the user of the race card is the feeling of nobility it can engender. While his opponent is condemned as racist--whether of the vicious intentional type, or the late middle-aged white buffoon to be pitied for his parochial attitudes--the user of the race card can congratulate himself on his superior enlightened outlook on the subject of race. The fact that accusations of racism without clear and unequivocal proof is a cowardly and despicable libel (in our present social milieu akin to a false accusation of rape) is irrelevant to its purveyors. It works. And considering all the benefits and advantages to be garnered--political, social, and psychological--it's perhaps easy enough to convince one's self that it's true absent any concrete evidence. The most tenuous of internal constructs upon which to build the case will do, such that Maureen Dowd can write an entire column of moral outrage based on a word she imagined Joe Wilson to have added (in his mind) after his "you lie!" outburst directed at president Obama in his speech to the joint session of Congress: "boy!"
Which brings me back to my original metaphor: the straw man. Hacking away at a straw man can infuse one with a sense of great skill and accomplishment--if one forgets that the straw man is not striking back. Point b of my earlier argument--the that the use of the race card leaves your opponent stupefied--creates this very condition. It's vital that conservatives, against whom the race card is so often played, craft an effective response and counter-attack to the spurious straw man accusation of racism. For every time it is used without answer it not only reinforces the user's self-image as morally superior, but also lends support to the picture of conservatives that leftists have carefully nurtured over the decades as a cohort of greedy, callous, angry white men, and prudish, punctilious, snobbish white women. It's time to pull the straw man down and replace him with a real, flesh and blood man who will fight back.