The RED HERRING is a common Logical Fallacy. Unfortunately, sometimes it is hard to pick up on, because of its Flagrant Absurdity.
It is the Literal, "COMING OUT OF LEFT FIELD", type of response. It catches many Debaters off guard, who try to find the Reasoning behind it, but cannot because it is Essentially Nonsensical.
It is used for many different reasons, and with a little practice can be a Formidable Weapon to create Doubt and Dissension among Opponents and Casual Observers.
It can be a Developed Skill, used to confuse the Issue at Hand, and directed at those unfamiliar with the Rules of Deductive Reasoning.
Naturally, there are certain Professions that can turn this Fallacy into an Effective Tool. It can be used to gain support, or influence others to make decisions that are not considered carefully, and without an eye towards possible Deception.
Here is an example;
Politicians- There are many issues that a Constituency might consider important, but for those Voters voicing opinions that might come across as Narrow Minded, Prejudicial, or Self- Centered, when viewed by the Opposition or the Undecided, an Unscrupulous Politician can provide a "RED HERRING" that creates a Scapegoat or Phantom Enemy, to justify the opinions put forth by that part of the Electorate.
Remember, the RED HERRING HAS NOTHING TO WITH TRUTH, FACTS, AND THE REALITY OF A GIVEN SITUATION. ITS ONLY PURPOSE IS TO HIDE THE ACTUAL REASONING BEHIND THE OPINIONS BEING EXPRESSED.
IT IS A FALLACY THAT LOOKS FOR EXCUSES TO EXPLAIN THE SUPPORT FOR CERTAIN ISSUES, OR THE JUDGMENT THAT IS BEING EXPRESSED ON GIVEN SUBJECTS.