Why jammed mower deck, now unattached, tractor dead?

LX178 with Pirhanna mulching deck.

My wife mowed soon after rain. The deck clogged, and the tractor stopped. But, it won't do anything, evem with the clutch switch un-engaged. I detached the deck, even turned the flywheel under the engine where the deck belt would go to see if it would move and it does.- its still electrically dead. Nothing happens when you turn the key.

Is there a kill sensor somewhere? Or is the clutch burned out? If so, why is the tractor DEAD?