Of all the things surrounding pearl harbor. I dont recall it being the Japanese comms that gave it away. IIRC they were under strict radio silence for that whole time period.
There was some warning, but it either was misunderstood (such as the early radar warnings) or the messages were delayed.
As far as the lusitania, I dont recall it being armed at all. It was carrying war materials, but I dont think it had any mounted deck guns like you implied.
(Can't edit posts since the last update)
Edit: torpedoes make less sense the more I think about it, but side turrets likely are why the ship was sunk. They probably shot down a recon plane, but who knows
I was halfway through responding to that in your initial comment. Torpedo tubes would require a massive retro fit. The lusitania was an ocean liner, so hard points for mounted cannons would be few and far between. There were most certainly armed merchant vessels with hidden cannons, but I dont think this was one.
(I really hope I dont come off as a dick here.)
I don't ever recall hearing or reading anything about the lusitania being any sort of belligerent. It was mentioned in a podcast earlier and the German reason for attacking was that it was suspected of transporting was materials. Which as far as I know, is totally substantiated.
The whole thing quickly became a propaganda piece by the British to bring America into the war. And churchill milked it for all he could.
With pearl harbor, that one is tricky, due to suppression of information and the passage of time. But from all I've found, the weight of the evidence falls to the oblivious surprise attack.
There were a couple indicators before hand, that in hindsight paint a clearer picture. But there were a several factors that resulted in the americans ignorance.
The PH thing I read in a book that was discussing declassified info that I think I still have. I'll have to look for it.
The lusitania didn't have deck guns, I didn't mean to imply that. Doors covering side turrets and likely torpedo tubes, but who knows. It was illegally armed for a civilian vessel
It has worked so well throughout history though. Everything from the Lucitiana to the Gulf of Tonkin to Pearl fucking Harbor. PH was an actual direct attack but we had plenty of advanced notice because their pilots wouldn't stop using their comms. Lucitania was attacked because it was a merchant ship with heavy weapons it should have never ever had installed. Tonkin was "let's pull up to three bad neighborhood and wait to be attacked" sort of situation. People like Bolton have seen this and use it part of their daily job to try and make wars, and it works sometimes.