That someone like Les Gelb says that "national security professionals" have career incentives to support US wars "to retain political and professional credibility" is amazing, yet clearly true. When I interviewed Gelb in 2010 regarding that quote, he elaborated that DC foreign policy experts - "national security professionals" - know that they can retain relevance in and access to key government circles only if they affirm the unfettered right of the US to use force whenever and however it wants. They can question tactics, but never the supreme prerogative of the US, the unchallengeable truth of American exceptionalism.
In sum, think tank "scholars" don't get invited to important meetings by "national security professionals" in DC if they point out that the US is committing war crimes and that the US president is a war criminal. They don't get invited to those meetings if they argue that the US should be bound by the same rules and laws it imposes on others when it comes to the use of force. They don't get invited if they ask US political officials to imagine how they would react if some other country were routinely bombing US soil with drones and cruise missiles and assassinating whatever Americans they wanted to in secret and without trial. As the reaction to Cornel West shows, making those arguments triggers nothing but ridicule and exclusion.
One gets invited to those meetings only if one blindly affirms the right of the US to do whatever it wants, and then devotes oneself to the pragmatic question of how that unfettered license can best be exploited to promote national interests. The culture of DC think tanks, "international relations" professionals, and foreign policy commenters breeds allegiance to these American prerogatives and US power centers - incentivizes reflexive defenses of US government actions - because, as Gelb says, that is the only way to advance one's careerist goals as a "national security professional". If you see a 20-something aspiring "foreign policy expert" or "international relations professional" in DC, what you'll view, with some rare exceptions, is a mindlessly loyal defender of US force and prerogatives. It's what that culture, by design, breeds and demands.
In that crowd, Cooke's tweets aren't the slightest bit controversial. They're axioms, from which all valid conclusions flow.
This belief in the unfettered legal and moral right of the US to use force anywhere in the world for any reason it wants is sustained only by this belief in objective US superiority, this myth of American exceptionalism. And the results are exactly what one would expect from an approach grounded in a belief system so patently irrational.