The Seattle Seahawks have stalled. They’re no longer the steamroller that crushed Peyton Manning in the Super Bowl last season and redefined how to defend the pass. At 3-3, they look mortal.

On the surface, this looks like just another post-championship hangover. The Seahawks might wish that were the case. Unfortunately for them, it goes much deeper than that. The real reason the Seahawks have fallen from the league’s elite is the dismantling of the secret to their success, which occurred months ago and won’t be easy to overcome...