The Impossible and the Unlikely

I really have to wonder what the Clinton campaign is doing right now:

Clinton declined to answer questions about Trump’s comments in Davie, and Kaine gaggle with reporters in Austin apparently called off.

— Hannah Chanpong (@hannahfc) August 9, 2016

If you were Clinton, how much time and money would you be spending prepping for the fight against Donald, and how much would you devote to the (unlikely though it may be) eventuality that Donald will drop out and be replaced by a real candidate? I ask not because I think that the latter is terribly likely, but because I really can’t see any other eventuality in which the GOP seriously challenges Clinton.