A common solution to the problem of evil is an appeal to free will: “God is wholly good, wholly omnipotent, and wholly omniscient, but he cannot interfere in human affairs because that would interfere with human choice.” However, in offering this as a solution, the assumption is made that in order for humans to have free will they must be capable of doing bad things. And not only should they be capable, but they must also actively cause evil; otherwise God could have it so that humans were free to choose their actions, but as perfect creations they always chose to do good. This, of course, would be a better (one entailing more good) outcome than the imperfect situation that is observed. Therefore God, defined as a wholly good being, would choose that option if it did not invalidate his “free will clause.” So, for free will to be a solution to the problem of evil, anything that has free will must entail evil.
But then one might whether God has free will? Yes? Then he causes evil and is not omnibenevolent. No? Then he is constrained by something and therefore not omnipotent. If free will is a solution to the problem of evil, then God is not God and in fact the notion of God is nonsensical. So, we have reductio ad absurdum, and unless the Christian theist would like to give up logic (this may be surprisingly common) , they had best find a better defense than this trite tactic.