comma before 'and' [conjunction]: he would ponder and then he would

[Calchas]

Standard punctuation calls for 'comma and' to join two independent clauses.
... the man would ponder for some time in silence, and he would answer something neither funny nor polite.

... the man would ponder for some time in silence and then, with a wet underlip pushing out from under the pipe like that of a feeding elephant, he would answer something neither funny nor polite. [Nabokov, The Aurelian]
Here, the comma is displaced. It no longer precedes the 'and.' Actually, it belongs to the absolute phrase 'with a wet underlip...'.

... the man would ponder for some time in silence, and then, with a wet underlip pushing out from under the pipe like that of a feeding elephant, he would answer something neither funny nor polite. [Nabokov, The Aurelian]
Is this punctuation possible? (yet it isn't what Nabokov did)

 

[entangledbank]

The comma joining two full clauses (your first example) is optional, not required. When you include it, and then add a supplement that requires commas either side to separate it intonationally, you get your third example. But this looks jerky, so it may look better to remove the unnecessary first comma - giving your second example. The two commas round the 'with' phrase are necessary, so only the first one is dispensable.

 

[Calchas]

Entangledbank, thank you for your reply.

Are you saying that the first two independent clauses do not require a 'comma and' because they are short and balanced?

 

[lucas-sp]

Well, they aren't that short. But the basic underlying sentence is indeed:

... the man would ponder for some time in silence and then he would answer something neither funny nor polite.

It's acceptable to suppress commas between clauses. I think Nabokov does so so that the reader moves quickly into the "and then" but then immediately has to stop, slow down, and process the "with-" phrase. It propels the reader into the end of the sentence, and then frustrates her expectations. It mirrors the action it's describing.

 

[MuttQuad]

Standard punctuation calls for 'comma and' to join two independent clauses.
... the man would ponder for some time in silence, and he would answer something neither funny nor polite.

... the man would ponder for some time in silence and then, with a wet underlip pushing out from under the pipe like that of a feeding elephant, he would answer something neither funny nor polite. [Nabokov, The Aurelian]
Here, the comma is displaced. It no longer precedes the 'and.' Actually, it belongs to the absolute phrase 'with a wet underlip...'.

... the man would ponder for some time in silence, and then, with a wet underlip pushing out from under the pipe like that of a feeding elephant, he would answer something neither funny nor polite. [Nabokov, The Aurelian]
Is this punctuation possible? (yet it isn't what Nabokov did)

I hate to get in the middle of this endless controversy; but as a writer, what I would do would be to use the punctuation you show in your first and third examples. Were I an English teacher, I'd demand an explanation from any student who did otherwise. In American usage, a comma (sometimes a semicolon) is needed to separate the parts of a compound sentence, and the mark is placed following the conjunction(s). (Chicago Manual, 15th ed. 6.32) A sentence with two very short independent clauses can get away without the comma -- but it would be a rare sentence I'd ever write where that applied.

 

[Calchas]

MuttQuad, thank you for your answer.

I believe that you are correct. I'm simply pointing out that this is not how Nabokov punctuates. I suppose that it comes down to a question of style. Nabokov's sentences are often long and complex, and he often breaks the rules. For myself, it doesn't bother me at all, but I just like to be aware of the rules. Admittedly, these rules shift depending on the nature of the text: a business letter is probably not going to punctuated as would a short story.

 

[MuttQuad]

True. Many writers know the "rules" but break them deliberately. I always feel that you have to know what the rules/customs are before you can make an intelligent decision whether or not to break them. That applies to a lot of things besides punctuation.