First, he is not a realist, but someone who went from being a pacifist anti-interventionist, who thought making nice would save the world. Then he transitioned to an idealist interventionist, as exemplified by the idiotic moves we took in Libya and Egypt and nearly Syria. Now he’s wallowing in incoherence, and he, our military, and the American people are exhausted by the ways our forces have been wasted to little effect in Afghanistan, Libya, and elsewhere.
Far from being a realist, Obama has no appreciation for the ways diplomacy must be backed up by force, credible threats of force, and the “fact of life” that diplomacy only work as a means of persuading another nation of some common interest or as a means of changing their perceived interests by the threat of imposing real harm. Finally, in all three phases of his foreign policy, he has never shown himself to have a coherent view of the US’s role, the limits of our power, and the times when our power may be called indispensable.
In short, he is an arrogant idiot who is harming the country.