Examples

1. “Albert Einstein, even after all his research into the nature of the universe, still believed in God. He once wrote, ‘I do not believe that the universe was the result of blind chance.’ If belief in God made sense to Einstein, then it makes sense to me.” (Hughes & Lavery, Critical Thinking, p. 151.) » Apart from the fallacious appeal to authority, Einstein’s beliefs about God are a matter of contention, many arguing that his occasional use of religious language was merely a poetic way of describing the majesty of the universe. So this may also be a case of misrepresenting or misunderstanding an authority.
2. “I saw a video clip of George Bush speaking to an audience that he called an ‘impressive’ crowd: ‘the haves, and the have mores’. He said: ‘Some people call you the elite, I call you my base.’ It is inexcusable that the President, who is supposed to be a servant of all the people, is catering only to the rich and powerful.” » Though some may consider this joke tasteless in any case, this footage, reproduced in Michael Moore’s Fahrenheit 9/11 without context, came from an annual charity fundraiser at which politicians are expected to poke fun at themselves. The comment was not to be taken seriously. On the flipside, at the 2009 White House Correspondents’ Association dinner, Obama made a similar joke: “Most of you covered me; all of you voted for me.” Even if there’s truth there, it’s easy to see how this quote could be similarly abused to establish authoritatively that the media is biased to the left.
3. “[I]n almost every litigated issue, eminent specialists can be found by both sides: some to testify that the blood is human, others that it is not human; some to testify that the signature is absolutely genuine, others that it is certainly a forgery; some to testify that a certain brand of canned meat is adulterated, others to affirm that it is pure.” (Foster, Argumentation and Debating, p. 62.)
4. “One of the most commonly printed quotes abut secrecy and secret societies in the U.S. was made by President John F. Kennedy in 1961. It is frequently used by conspiracists to show that Americans distrust secret societies: ‘The very word ‘secrecy’ is repugnant in a free and open society; and we are as a people inherently and historically opposed to secret societies, to secret oaths and to secret proceeding.’ Of course, like any sound bite, the part that gets left out is that Kennedy was actually giving a Cold War-era speech in favor of secrecy. He was asking a ballroom filled with newspaper publishers to keep their mouths shut about U.S. government activities and to not print anything in their papers that might give ‘our enemies’ an advantage.” (Hodapp et al., Conspiracy Theories and Secret Societies for Dummies, p. 15.)
5. “I received an email from a friend that lists no less than ninety-two books that Governor Sarah Palin requested be banned from the Wasilla Library in 1996. It says the list was recorded in the official minutes of the Wasilla Library Board. It even includes the Harry Potter series. We should not vote for a censor like Palin who disregards the First Amendment.” » While multiple sources attest that Palin did ask some worrisome questions of then librarian Mary Ellen Emmons, the problem here is that a chain-email is not a reliable source and the reader has no access to the Wasilla Library Board minutes to verify the claim. A red flag here is also the inclusion of the Harry Potter books which had not yet been published in 1996. Urban Legend debunkers subsequently tracked down the real source, a list of “Books Banned at One Time or Another in the United States”.
6. “Ward Churchill tells a shocking tale of war crimes committed by
   the U.S. Army at Fort Clark against the Mandan Indians in 1837. Fort Clark stood perched on a windswept bluff overlooking the Missouri River, in what is today North Dakota. Churchill reports that in early 1837, the commander of Fort Clark ordered a boatload of blankets shipped from a military smallpox infirmary in St. Louis. When the shipment arrived at Fort Clark on June 20, U.S. Army officers requested a parlay with Mandan Indians who lived next to the fort. At the parlay, army officers distributed the smallpox-infested blankets as gifts. … While the Mandans and other Indians of the Upper Plains did suffer horribly from a smallpox epidemic in 1837, Churchill presents no evidence whatsoever to indicate that the infection was anything but accidental, or that the U.S. Army was in any way involved… In telling his fantastic tale, Churchill has fabricated incidents that never occurred and individuals who never existed. Churchill falsified the sources that he cited in support of his tale, and repeatedly concealed evidence in his possession that disconfirms his version of events. (Brown, “Did the U.S. Army Distribute Smallpox Blankets to Indians?” in
   Plagiary, Vol. 1, No. 9, p. 1.)
7. “‘If torture isn’t wrong, then nothing is wrong.’ ~ Abraham Lincoln” This quote, bandied about in discussions of the ethical status of torture, is in fact a distortion of Abraham Lincoln’s words after signing the Emancipation Proclamation: “If slavery is not wrong, nothing is wrong”. In 1863, Lincoln did issue a military mandate, the Lieber Code, that included a prohibition of torture, so Lincoln can surely be enlisted in arguments against torture. Nevertheless, to distort his words — however pithy, unequivocal, and serviceable they are — is an inappropriate appeal to authority. (The appropriation of the quote may have started here.)
8. “Like most conspiracy books, The Lincoln Conspiracy has many footnotes and an impressively long bibliography. But, also like most conspiracy literature, it’s a circular citing process, with conspiracists endlessly referring to one another’s work. Despite their abundant cribbing from an earlier conspiracist work from the 1930s by an Austrian chemist name Otto Eisenschimi, the authors claimed to be the only investigators in history who’d ever gotten the story of Lincoln’s assassination right. They also seemed to have connected with an amazing number of documents to back up their version of events, papers, and diaries that had slipped past mere mortal historians. The book’s opening pages were touting these miraculous discoveries, as well as the sever scientific methodology they had put to use in their quest. … But when you read on carefully, you come across the following astonishing statement: ‘The authors acquired a full transcript of the contents of the missing pages and had the contents evaluated by historical experts, but have not been able to acquire copies of the actual pages to authenticate the handwriting.’ What these guys are saying is that they haven’t seen copies of the actual ‘million dollar’ diary pages in which they’ve built just about the entire thesis of their book.” (Hodapp et al., Conspiracy Theories and Secret Societies for Dummies, p. 12.)

Critique

Show that either: 1) the person cited is not an authority in the field; or, 2) that there is general disagreement among the experts in the field on this point; or, 3,4) that the authority is being misrepresented; or, 5) that the source is not reliable. Of course, even when an authority has been cited appropriately, reasons can be offered for dissenting from said authority.