As you can see, the poster above comes from http://bewareofimages.com. While I do not support some of what is on the site, they are good at pointing out deliberate lies, inadvertent lies, omissions of truth, etc. I find the poster above to be a quite good one. It lists the most common logical fallacies found today, and most certainly the fallacies that are used deliberately in much of our political dialogue. Note that there are many many more fallacies that can be committed or misused. These are just the most egregious ones currently.
Ad Hominem – the most common expression of the Argumentum ad Hominem is when you find yourself dismissing someone’s argument simply because of their other political opinions, or because of their race, or because of their work, etc. So, for instance, when you find yourself thinking that of course s/he would say that s/he is a [Democrat or Republican], you have committed that fallacy. At times folks have wanted judges removed because they are of a particular race, on the grounds that they could not possibly be impartial. This fallacy is dangerous, because it is so easy to get yourself to believe that a person is influenced by their party or race or job to the point that they are no longer able to reason correctly.
Faulty cause – see an example below:
The only policy that effectively reduces public shootings is right-to-carry laws. Allowing citizens to carry concealed handguns reduces violent crime. In the 31 states that have passed right-to-carry laws since the mid-1980s, the number of multiple-victim public shootings and other violent crimes has dropped dramatically. Murders fell by 7.65%, rapes by 5.2%, aggravated assaults by 7%, and robberies by 3%. — "The Media Campaign Against Gun Ownership", The Phyllis Schlafly Report, Vol. 33, No. 11, June 2000
The paragraph above is an example of the faulty cause fallacy. It is a particular example of what is called the Post Hoc, Ergo Propter Hoc fallacy. Why is the paragraph above fallacious? Because the crime rate fell all over the country from the mid-1980’s onward, whether or not the handgun laws were changed in that locality. In fact, the same argument has been used for stronger criminal laws being the cause of the decline. Other causes have also been adduced for the phenomenon. In every case, one can show states for which the proposed reason was not present, but the crime rate declined.
I will not go into the rest of the fallacies above, but you can come up with your own examples. I will say that the guilt by association is one of the most despicable ones, and is one of the ones most often used in today’s discourse.
The biggest danger of these fallacies is that we can end up believing things that are false and/or dangerous to ourselves and to our country. Worse, they can lead us to silence others, mistreat others, and even to pull us into an unjustified war. There is a reason why Saint James, in his epistle, commented that the tongue can set a whole forest afire. Few things are more dangerous than a fallacy that is believed and then spread to others.