This time, the junta managed somewhat to conciliate the positions for Sanchez and Duarte also signed the new communique.
This is an excellent example of why it's important to use commas after what are called "conjunction" words. In this above sentence, as we read, it seems that the junta conciliated the positions for Sanchez and Duarte, but then the sentence seems to end abruptly. This forces us to re-read the sentence and realise that the junta conciliated the positions (positions that were explained in the previous paragraph) because Sanchez and Duarte also signed the document.
The role of conjunctions is to join ideas of equal importance. For example, look at the following sentence:
The man was short and bald.
In this sentence, the author of a sentence like that would want the reader to note the equal importance of the man being both short and bald.
For this post, my intention is not to focus on conjunctions so much as when to use commas and conjunctions. A comma should always be used when a conjunction is used to join 2 main clauses (phrases that function on their own as sentences). Look at the following sentence:
It was a cold day, for the wind was blowing.
I often see the commas omitted in these types of sentences. Quite honestly, the readability of the above sentence would not be too affected, but as we can see in sentence about Sanchez and Duarte above, not having used a comma caused the sentence to be confusing on first reading of it. I always try to promote getting into the practice of always using commas to join 2 main clauses because then it becomes habit, and that will hopefully help to prevent you from creating any confusion.
If you'd like to know what the conjunctions are, see the list below: