Kings used to lead their own armies. They used to lead the cavalry’s charge. For a king to send an army to war and remain behind to warm his throne was simply not done. Those that tried it lost their thrones, and some lost their heads — to their own people. It was a useful check on political and military rashness. It hasn’t been that way for a long time. Today armies go into the field exclusively at the orders of politicians who remain at home. And politicians are bred to believe that reality is entirely plastic to their wills.
On the strength of this one quote, I bought the book.