[simonh]

Agreed, it's just a recent example but not a particularly good one. One possibility he doesn't consider is that we knew these weapons were likely to be used soon, but didn't have the knowledge or capability to target them effectively. Another issue is that even if you don't reveal sources by making information public you can affect the opposition's behavior. Announcing that Assad was about to use chemical weapons might have prevented him from doing so, or conversely might have persuaded him to use them even more liberally before they get taken out by strikes.