Dirimens Copulatio: mentioning a balancing or opposing fact to prevent the argument from being one-sided or unqualified:

• This car is extremely sturdy and durable. It's low maintenance; things never go wrong with it. Of course, if you abuse it, it will break.
• . . . But we preach Christ crucified, to Jews a stumbling block, and to Gentiles foolishness, but to those who are called, both Jews and Greeks, Christ the power of God and the wisdom of God. --l Cor. 1:23-24 (NASB; cf. Rom. 13:4-5)