My Twitter feed is mocking the policy behind this news report, but of course it makes perfect sense. Here goes:
1. The United States wishes to have it be common knowledge that it can embarrass Putin. But in fact maybe it can’t! (At least not with a policy we are willing to bear the consequences of.) So why not threaten that you can? A truly secret strike probably would hurt him less than an embarrassment. So start investing in the embarrassment now.
2. If the U.S. does do something cyber against Russia, it may wish to signal in advance that it won’t be truly severe, so as to limit retaliation and lower the probability of ongoing escalation. Some public discussion can achieve this end. Truly devastating blows are in fact usually delivered in secret.
3. There is a chance that the U.S. can’t/won’t do much if anything against Russia at all. In that case third parties (Iran, China) may not know this for sure, and the announcement may have a slight deterrent value in their direction.
4. It may not be possible to understand the entire American strategy without knowing the private messages that are being sent to Putin at the same time. For instance, the overall strategy may be “announce a coming mild retaliation and privately threaten a more severe action.” Is that really so out of place? Probably not.
In other words, “announced secrets” sometimes can make perfect sense.