The classic problem that can be observed throughout history in regard to warfare is that political leaders often find it difficult to find Admirals and Generals who are competent at making war while also being sufficiently political. There’s awfully good reasons for that, if you think about it.
Take a look here. I can’t tell you how much that makes me laugh. I was the kind of Navy officer who did well because I usually said more than I should from a
non-ass-kissing political standpoint, but I could always pull it off. Brutal honesty and rash judgment; it’s always worked for me more than not. Even while on exchange with the French Navy, amongst a lot of old-money, well-known-family French officers doing their time like the men in those countries do, I could pull it off. The old crusty Captain of one of the ships I served on used to call out to me during various gatherings just to have me recite some rant or other he’d heard me say, or heard about. I was renowned as "très dure."
"C’est vrai, non?" he’d ask everyone.
I don’t know anything about Petraeus, but I know what I think I see when I look at that photo of Fallon: ‘No Bullshit. Not now; not ever. None from me; and I aint about to eat any of yours.’ Hope I’m not wrong about that, if he does testify.