Sentence structure

Hey Sanjay,

What an unusual situation, trying to answer a question about my own sentence in an earlier post!  But I might be the best person to answer, or at least the guy who ideally should go first.

absent that means "if that is not true" or "if that is not the case".  I'd never thought about it before, but it looks like an alternative to an if-clause. (Interestingly, the Oxford online dictionary tells me that, in this sense of the word only, absent is a preposition.  Also, that this sense of absent [something] is more common in North American English.)

from what I have been able to glean means "based on what I have learned or understood so far".

Prepositional phrases such as these, when placed in the middle of a sentence, are typically set off by commas.  Some writers, myself included, tend not to place a comma before a short phrase like absent that when it follows another comma (summary, but) in such close proximity.  Others would fully set-off the phrase (summary, but, absent that,...).

The purpose of both phrases is to qualify the statement I make at the end (the patterns I have outlined apply to all countries that belong(ed) to the British Commonwealth)  That statement is only true if I am not mistaken, and it is also based on what I have learned or understood about the topic so far.  In other words, I am a hopelessly neurotic, insecure person.  LOL

I hope this helps.