FDR was VP nominee because he was (superficially) just like Teddy! NY State politics -> Assistant Secretary of the Navy -> VP!
The way Washington politics worked back them, the Secretary of the Navy was often someone who was appointed for political reasons rather than ability, while the Assistant Secretary of the Navy was the person who actual ran the Navy.
Stick close to your desk and never go to sea and you all may be Rulers of the Queen's Navee!
I can hum a fugue of which I've heard the music's din afore, and whistle all the airs from that infernal nonsense Pinafore.
Crap, that'll be stuck in my head all day now.