Deader than a Kennedy

The epitome of death. A profound state of deadness, where death is thorough and is firmly established.

To ascertain death at the top-most level, surpassing even a Kennedy's seemingly effortless ability to achieve it.

Exponentially Dead.
Deader than fried chicken.
Pretty freaking dead.
Can pertain to a person literally or figuratively to their career, chance of success, etc.; or to a place where no one goes; or to a thought or idea with no chance of acceptance.

"This place is Deader than a Kennedy"
"Probably because it's a shopping mall."

"Do you think Gruden will ever coach again?"
"No, he's Deader than a Kennedy to the NFL!"