Take the following example sentence:
"She was concerned that in spite of her recent requests, he wouldn't accept her proposal on time."
Since there's a comma after 'requests', aught there to be one at the beginning of the propositional phrase--before the word 'in'--making it a non-restrictive modifying phrase?
As the above sentence stands--without the second comma--am I to interpret the preceding clause before the comma as a nonessential element?
I hope people see what I'm getting at. The included comma obviously enhances the readability of the sentence, and it feels natural to include it but, strictly speaking, isn't the single comma incorrect? Two commas are required, no?
If this sentence is fine, can sobody explain the logic from a syntax perspective?
Thanks for any responses.