Constraint theory defines for you what outcomes are possible and what outcomes are impossible. It also eliminates wishful thinking.
Success looks like you sitting here pretty confident that an armed brigade isn't going to come pouring in here and blow your head off. Which I don't think is your major concern. Therefore, the United States' foreign policy is successful.
One of the great weaknesses of journalists is they interview people and they think that's important. They think that they are going to show them their true hand. But more to the point, they're trapped.