The presentation of a good argument has a number of important components. Having your facts correct (and sourced), the tone and timbre of the argument, and understanding the tools of debate; in particular, having an understanding of fallacies.
Similarly, understanding an opponent's argument and rebutting it requires similar components.
Here at the Daily Kos (and in political debate in general, truth be told), I see an awful lot of misidentification of fallacies. Quite often, folks can see that an argument is logically weak, but they don't correctly identify why it is a weak argument. This lessens the quality of the rebuttal.
So - do you know your fallacies? Let's start with a little quiz here.
Each of the following arguments contains at least one fallacy. Can you identify them?
1. Gay marriage is bad because the bible says it is, and given that we've always been Christian nation, we must maintain our righteousness in our laws.
A Appeal to Authority.
B Red Herring.
C Appeal to Emotion.
D Appeal to Tradition.
E Strawman.
2. Marijuana is harmful, and should never be used. If it wasn't, it wouldn't be illegal.
A. Strawman
B. Begging the Question.
C. Confusing Cause and Effect.
D. Guilt by Association.
E. Red Herring.
3. JRandomPoster is a real douche. Therefore, his argument is false.
A. Strawman.
B. Ad Hominem.
C. Bandwagon.
D. Poisoning The Well.
E. Appeal to Flattery.
4. JRandomPoster is a developer, not a political scientist. Therefore, his political argument is false.
A. Strawman.
B. Ad Hominem.
C. Bandwagon.
D. Poisoning The Well.
E. Appeal to Ridicule.
5. GLBT people say want the right to marry, but what they really want is for everyone to have to marry someone of the same sex. Thus, there should be no gay marriage.
A. Strawman.
B. Poisoning the Well.
C. False Dilemma.
D. Appeal to Common Practice.
E. Begging the Question.
Answers: 1 - B and D (with a valid argument for both A and C), 2 - B, 3 - D, 4 - B, 5 - A.
So, how'd you do? Don't feel too bad if you got a bunch wrong - most folks do.
When you are debating someone, correctly recognizing the fallacies in their arguments is extremely useful in addressing their points. Being able to correctly identify fallacies makes your arguments significantly sharper; furthermore, as with any thought based tool, such knowledge allows more precise thinking.
Additionally, knowledge of fallacies will keep one from overly using them when debating. For example, it might be tempting to drift out into fallacy land when canvasing or phone banking, but it is dangerous territory. You might get away with it sometimes, and maybe even get some votes, but folks can often recognize weak arguments even if they can't identify the formal reason as to why the argument is weak. Odds are, if you go overboard on your pitch in these conditions, you'll lose more votes than you'll gain.
There are quite a number of web based references out there. Personally, I keep a guide of fallacies as a hot button on my browser bar. The best quick reference I've found is here:
http://www.nizkor.org/...
For more in depth reading on the web, I'd check out these:
http://www.fallacyfiles.org/
http://changingminds.org/...
http://www.don-lindsay-archive.org/...
So - good luck, and happy debating!