Allied intelligence might hear reports of the ship, but verifying them before satellite reconnaissance would require an agent to penetrate deep into the Soviet Union and photograph operations. The distinction between knowledge and proof explains why secret German-Soviet military work could be suspected without producing evidence strong enough for diplomatic action. The Caspian location therefore offers concealment through access difficulty rather than perfect secrecy. A likely pattern can be reconstructed from surrounding evidence without being presented as an archival smoking gun.
Notable Point · 28:12-31:00
Caspian secrecy and the intelligence proof problem
The Caspian's isolation could make Allied awareness of a carrier project much easier than obtaining decisive proof of it.