Willpower is not some mythical force that we either have or don't have. Willpower is our decision to use higher mind thinking instead of lazing around in the clutches of our primal mind.
I'm newly widowed, so I've gone from having a life partner, and having another brain to make decisions with, to doing it all on my own and questioning what I'm doing. I have to be a calmer person, because my anger can look pretty terrifying to a young person.
In a time of war, the president must have the power he needs to make the tough decisions, including, if need be, the decision to grant himself even more power.