A Wikipedia list of famous speeches includes this entry:
1873: The “Is it a Crime for a Citizen of the United States to Vote?” speech by Susan B. Anthony, who in her effort to introduce women’s suffrage into the United States asked her fellow citizens “how can the “consent of the governed” be given if the right to vote be [sic] denied?”
That little “[sic]” there is the pedant’s favorite mark; and it’s always a dangerous one, because the pedant may easily find himself hoist by his own petard (the petard was apparently some sort of Elizabethan hoisting device, probably an ancestor of the modern forklift). The Editor is a card-carrying pedant himself, but years of embarrassment have at last taught him not to be quite such a showoff.
“Sic” is Latin for “thus”; it’s most often used to indicate that a mistake is in the original quoted material, and hasn’t been introduced by the current writer. In this case, however, Susan B. Anthony didn’t do anything wrong. She was using the subjunctive form of “to be,” which in the nineteenth century was correct in a clause beginning with “if.” Besides, the Wikipedia editor has neglected to change the quotation marks around “consent of the governed” to single quotes (since it’s a quotation within a quotation), in one sentence committing an obvious error and mistakenly marking a correct construction as an error.
What’s the moral here? You can avoid embarrassment by using “[sic]” sparingly, if at all. If your quotation has an obvious typing error, just correct it silently. If the quotation is ungrammatical, let the error stand without remark, as long as the meaning is clear. You’ve protected your own reputation enough by putting it in quotation marks.