A theory…
(C)apital before Camp (D)elta
The old capital building was used in the Civil War to hold and execute treasonous spies. (pic of gallows)
Prison in the basement of the Capitol
https://twitter.com/TrueCanuck11/status/1350074145153945600?s=20
Multiple meanings may exist. Tons believed it meant Comey before Declas too.
Seems possible considering their building a prison around the whole Capital.