Jay Evensen: How do we know when a politician has lost it?

SALT LAKE CITY — The day we really knew my father had dementia was when a doctor asked him what year it was and he answered, tentatively, “1948?”All the suspicions and doubts, the inclination to pass things off as minor lapses, suddenly crystalized. Other questions followed. Who is the president? Where are we? He couldn’t answer.Once the family was sure of the diagnosis, the preceding few years suddenly came into focus.Things we had thought were one-time “senior mom