Much of this discussion occurs in the context of substantially increased antagonism and instability being reported by the US Military.  Mid air confrontations with Russia (not to mention open diplomatic hostility), very provcative actions by China in the South China Sea and in the air, NK and Jong un reveling in the pressure and leverage he is creating with this nuclear and missile advancements.
US mid air incidents with an Iranian drone.
All under Trump.  All racheted up in about 7 months.
Trump has ushered in OPEN NUCLEAR THREAT TO THE US.
IF McMaster is a vestige of the Obama Admin, and McMaster is being neutralized and opposed or contradicted by some sort of "new" Trump admin. doctrine, then logic dictates that McMaster be allowed to prevail and have the final word.  Obama never caused the type of international instability that Trump has orchestrated within only 7 months.
Right now, the emerging "Trump Doctrine"  has the US staring down the barrel of a three or four front war.