It is possible that she got a diagnosis of metastasized cancer or amyotrophic lateral sclerosis (Lou Gehrig's disease -- my dentist was diagnosed with this when he was about her age) or some other deadly condition and doesn't want the public to know about it until she is out of office and can spend the rest of her days with her family.
Just a possibility to bear in mind.
Baritonobasso
"The students are overstimulated. Willie, remove all the colored chalk from the classrooms!"
