Today we would like to discuss the use of commas before the conjunction ”because”.
The word ”because” is a subordinating conjunction, and that means it connects a subordinate clause and an independent clause.
With the exceptions of conjunctions “whereas” and “although”, we do not write a comma when the subordinate clause comes after the independent clause.
For example, let us look at the sentence “I left the party because I felt excluded.”
In that sentence, “I left the party” is the independent clause, and “I felt excluded” is the subordinate clause, and ”because” is, in that case, the subordinating conjunction. Therefore, there is no need for a comma because the sentence makes sense without one.
The only instances when it would be wise to write a comma before the subordinating “because” is when we risk ambiguity in meaning and when we want to correctly describe why something did not happen. That enables the reader to know that the “because” clause gives the reason for the negative statement.