Why a secret weapon cannot deter

Can an unannounced or secret capital asset still provide deterrence?

No; secrecy may protect details, but an adversary must know the capability exists for it to shape decisions before conflict.

A weapon or capital asset cannot influence an opponent's prewar calculation if the opponent does not know it exists. Deterrence requires the adversary to believe that a capability is real and could be used. States therefore reveal the existence of strategic arsenals while protecting many operational details. The comparison with Soviet, Chinese, and North Korean nuclear forces shows why visibility is part of the capability's deterrent function rather than a surrender of every secret.