This is a curious assertion, especially since Gelb spends much of the next 3,000 words supplying historical evidence for precisely the opposite point of view: presidents have in large part ignored domestic criticism and succeeded in enacting policies that ranged from the grievously wounding to the mildly successful.
The only real support Gelb provides for his thesis statement comes in the form of fact-free assertion about the Obama administration's purportedly craven pursuit of popular policies "where it has little faith its efforts will succeed," as in the case of Iran, North Korea, Middle East peace, and Afghanistan. To which I can only muster a disinterested and disbelieving "meh."
All of this is more than a little galling coming from the man who perhaps more than any other represents the embodiment of the American foreign policy commentariat's uncritical pro-executive consensus -- and this at his own word. On the subject of the Iraq war, here's Gelb's unashamed explanation:
My initial support for the war was symptomatic of unfortunate tendencies within the foreign policy community, namely the disposition and incentives to support wars to retain political and professional credibility.