I think that MacMillan overstates his argument. Aside from the two influential people he mentioned, Kissinger and Mearsheimer, I haven't seen any other evidence of division. To be sure, I was surprised to read their dissenting opinions in ruling class oriented publications, but I think they constitute a minority of two.
With no end in sight for a lasting resolution to the crisis in Ukraine following the Western coup in Kiev, U.S. strategists are increasingly becoming polarised over future policy in the region. The belligerent and antagonistic policies of the war-hungry neoconservative movement are pushing the world closer to war with Russia, while other major geopolitical figures in Washington are advocating a de-escalation of the situation and an inclusion of Russia in serious dialogue.