[Warning: This is a post that is entirely a non-sequitur – or not. Read it and leave a comment about what you think.]
Abraham Lincoln, in an letter to supporters of Millard Fillmore as a third party candidate in the 1856 presidential election, summed up his arguments why Fillmore wasn’t likely to win in Illinois with an interesting simile: “As plain as the adding up of the weights of three small hogs.” 
Did you know that non sequitur is an interesting Latin term that “wears many hats!” It serves as the name of:
- A writing technique (literary device) – an irrelevant, often humorous comment to a preceding topic or statement;
- A sequence of missteps in logic (logical fallacy) – a stated conclusion is not supported by its premise and therefore the conclusion is arbitrary;
- A comic strip (by Wiley Miller) – a comedy strip with political and satirical overtones;
- A TV episode (Star Trek: Voyager – Season 2; Episode 5) – where a spacecraft accident causes a Voyager crew member to fall into a “time-stream” and enter an alternate reality where he was never a part of Voyager’s crew.
In everyday usage, we use non sequitur to refer to a comment where the last part is totally “out of whack” to the first part – in other words, it doesn’t make sense [a sort of less structured logical fallacy].
For example, the way I began the blog with Lincoln’s quote and then shifted to a Latin term = out of whack!
Another example of this type of non sequitur [out of whack] is the one that is/was a hot news topic – Trump’s presidential letter firing his now former-FBI Director James Comey.
Trump writes [bolding is mine for your attention]:
...I have accepted their recommendation and you are hereby terminated and removed from office, effective immediately. While I greatly appreciate you informing me, on separate occasions, that I am not under investigation, I nevertheless concur with the judgement of the Department of Justice that you are not able to effectively lead the Bureau.
[“…their recommendation…” refers to Deputy Attorney General Rod Rosenstein and Attorney General Jeff Sessions.]
The term non sequitur wears so many different hats – an episode of alternate reality, a political/satirical cartoon, a sequence of missteps in logic, an often humorous comment about a previous statement, AND an everyday term for an “out of whack” comment that doesn’t fit the conversation.
So, in summary, Trump, his letter for firing Comey, the everyday use of the term non sequitur, as well as all the different uses it has (including the Star Trek plot line) really are NOT unrelated, and that is…
“As plain as the adding up of the weights of three small hogs.”
Food for thought.
 “Letter to Supporters of Millard Fillmore (September 8, 1856)”, A Treasury of Lincoln Quotations (1965) by Fred Kerner, p. 255. Also found in: “Form Letter to Fillmore Men” Collected Works of Abraham Lincoln. v.II:374.
 Balz, D. (2017, May 11). The shocking firing of James B. Comey puts new pressure on Trump and his team. Https://www.washingtonpost.com. Retrieved May 11, 2017.