It is not desire to do the good thing or the right thing, it is rather the problem of not knowing what the right thing is. What is needed here is more knowledge and better ways of knowing-more information and finer methods of discerning right from wrong. The point is that if we know what is right we will do it, or at least we will be able to do it, if we choose. Our society assumes that if we know what is right, what is good, we will do it.
Ignorance is the problem, education the cure.
Safe and peaceful neighborhoods and honest business dealings are the result. But Paul, dare I say it, is a much better judge of humanity than, say Dr. Freud or Rush Limbaugh because Paul recognizes that neither knowledge nor desire are enough to bring about goodness and happiness. Knowledge, or knowing something like the law in Romans 7, only makes the problem worse, and desire just adds to our guilt. First, that our desire for the good comes from God-to seek the good is to seek God around us. And second, in failing to be able to do the good we desire, to be unable to act on our desire, we are not without comfort and consolation for this is why the Church was formed, why we pray and commune together.