Question: According to the Wikipedia page for the [Oxford Comma](http://en.wikipedia.org/wiki/Serial_comma#Arguments_for_and_against), "Use of the comma is consistent with conventional practice" and "Use of the comma is inconsistent with conventional practice." Did the Oxford Comma come before its omission, or was the Oxford Comma traditionally omitted?

It makes logical sense that every item in a list would be separated in the same way: by a comma. If the Oxford Comma is conventionally correct, when and why did people begin to omit it?

Answer: 
There are situations where use of the [Oxford comma](https://en.wikipedia.org/wiki/Serial_comma "(a.k.a. serial comma or series comma)") will make or break a sentence.

**Choose a style and *be consistent*.** When you run into a situation in which your choice suggests a misinterpretation of the sentence, rewrite it in another manner to avoid the confusion.

Consider these two pairs where the Oxford comma makes (1) or breaks (2) the intention:

> 
> **Oxford comma:**
> 
> 
> 1. *We invited the strippers, JFK, and Stalin.* = Strippers and JFK and Stalin.
> 2. *We invited the stripper, JFK, and Stalin.* = JFK (the stripper) and Stalin.
> 
> 
> **No Oxford comma:**
> 
> 
> 1. *We invited the strippers, JFK and Stalin.* = Strippers named JFK and Stalin.
> 2. *We invited the stripper, JFK and Stalin.* = Stripper and JFK and Stalin.
> 
> 
> 

A picture (from [Joe Kessler's blog](http://lesserjoke.tumblr.com/post/17114988391/captainrobocop-politicalprof-the-oxford)) to better illustrate this:

[![The Oxford comma alters the subjects of these sentences](https://i.stack.imgur.com/spQkb.png)](http://lesserjoke.tumblr.com/post/17114988391/captainrobocop-politicalprof-the-oxford)
I don't have information about the history of this, so I'm just responding to the second part of your question. Why should there be no comma before 'and'? The answer is simple - there has never been a convention for adding a comma (as far as I know) for mentioning two items: *I like apples and oranges* or *She doesn't mind running or swimming*. The problem comes when you want to add a third item: *I like pears, apples and oranges* or *She doesn't mind jogging, running or swimming*. It must seem fussy to people to insist on a comma before 'and' here, if there was no comma for two items.