Comma placement in a "parenthetical expression preceded by a conjunction"

Solution 1:

Background

First, I don't find the statement "If a parenthetic expression is preceded by a conjunction, place the first comma before the conjunction, not after" in my 1979 edition of Strunk and White (Macmillan, 1979), but I do see it in the on-line version (May 1995).

Second, in the 1979 edition under the rule "Enclose parenthetic expressions between commas", the authors state:

"This rule is difficult to apply; it is frequently hard to decide whether a single word, such as however, or a brief phrase is or is not parenthetic."

So, I'm not sure it's correct to attribute the statement "If a parenthetic expression is preceded by a conjunction, place the first comma before the conjunction, not after" to Strunk and White; after all, they were long gone by 1995. Also, Strunk and White acknowledge explictly in the 1979 edition that the rule is difficult to apply, which means to me that at times some judgment may be required.

Your Question

In your question, you state:

I disagree with the comma placement in the following example: "He saw us coming, and unaware that we had learned of his treachery, greeted us with a smile."

To me, it makes more sense to place the comma after "and", not before it. That is, to write: "He saw us coming and, unaware that we had learned of his treachery, greeted us with a smile."

I wouldn't go so far as to say your usage is wrong, because I don't think it is -- I understand the logic and sense of it -- but I prefer Strunk and White's placement. To me, the sentence sounds better when I read it out loud, at least the way I read it out loud. How it sounds is what matters. I'm not sure the following is grammatically correct, but I sometimes use two commas:

He saw us coming, and, unaware that we had learned of his treachery, greeted us with a smile.

For me, this sometimes lines up well with the pauses in the sentence, and it is not inconsistent, or at least not entirely inconsistent, with the 1979 edition of Strunk and White. In any event, we now have all three possibilities out on the table: comma before the "and", comma after the "and", comma before and after the "and".

Solution 2:

It should be obvious even to Strunk and White that any uncertainty about the position of the first comma will be resolved by dumping everything between the two…

Although a few of us might still use it, the third comma in "He saw us coming, and, unaware that we had learned of his treachery, greeted us with a smile" is largely anachronistic and in any case, serves only to confuse the issue.