I've recently heard these two examples where I don't understand what "a" is supposed to emphasize:
What this emphasized "a" supposed to mean?
The indefinite article 'a' here emphasizes indefiniteness in the response.
In the first question, a word is left implicit: "Do you believe in [this] God?" (In the North American/European tradition, at least, 'this God' is almost certainly the Christian one.) The reply "I believe in a God" affirms some brand of theism, but leaves intentionally ambiguous which God is meant, or perhaps signifies that the replier means a different God. Or more than one, as a commenter suggested.
In the second case, I expect that the (specific) "primary conflict" about to be discussed is—at first glance—the primary conflict, the conflict to which all others are secondary. But clarifying to a primary conflict leaves open the possibility that other sources of conflict might compete, even with equal importance. To me, the sentence sentence feels natural as an invitation to think critically about other possible sources of conflict. It might be given for instance by a lecturer.
