It doesn't change the meaning and import of what the Mercury was saying, though. Nobody doubts that they put things this way: "The issue before the country is the extinction of slavery."
"I would have left that in if I'd had the original text."
You are covering up your intent to publish misleading quotes by acting as if you would have been forthright "if I'd had the original text." The original text is just as readily available as your version, and you are intentionally trying to pass off your quote as valid when it was nothing but propaganda.
Therefore this statement >>> "I do notice that different versions of the quote appear on the Internet" is nothing but a cover up of the fact that you chose a quote that was entirely out of context, and left out the phrase that gave support to my argument.
And here you try again to misrepresent the article: "It doesn't change the meaning and import of what the Mercury was saying"
Of course it does, and you know it.