How presidents should treat generals

I was checking something in Eliot Cohen’s classic Supreme Command, the best book every written about how presidents should handle generals, when I noticed this very good summary of last week’s events:

Generals are, or should be, disposable. Statesman should not, of course, discard them thoughtlessly, nor should they treat them discourteously. Yet all four of these statesman [discussed in the book] showed themselves able to treat generals in line with Gladstone’s first requirement for success as a prime minister: ‘One must be a good butcher.’ Indeed, it was the most mild-mannered of the four, Lincoln, who relieved commanders the most frequently."

As we digest the McChrystal blowup, those are words worth keeping in mind.