Story highlights Gayle Lemmon: McMaster assumes his new national security adviser role in America that is at war but does not act like it

For the most part, its citizens are insulated from the fights waged in their name, she says

Gayle Tzemach Lemmon is a senior fellow at the Council on Foreign Relations and author of the New York Times best-seller, "Ashley's War: The Untold Story of a Team of Women Soldiers on the Special Ops Battlefield." The opinions expressed in this commentary are hers.

(CNN) For days after the dramatic resignation of Lt. Gen. Michael Flynn -- followed by Ret. Vice Adm. Bob Harward's rejection of President Donald Trump's offer of the job -- America remained without a permanent national security adviser.

Now, Army Lt. Gen. H.R. McMaster has stepped up for the job.

Gayle Tzemach Lemmon

McMaster's arrival amid the headline-grabbing upheaval in America's national security infrastructure comes at the same time America pursues plans for expanding its wars abroad. What we are witnessing is a profound mismatch between America's desire to project stability around the world and its inability to establish stability at home.

America is a nation at war that does not act like it. For the most part, its citizens are insulated from the fights waged in their name. The result? Americans don't demand and prize stability in their national security infrastructure in part because the consequences are so hidden from their sight.

But there is a danger in that distancing. Particularly as our nation's leaders consider sending more troops to Afghanistan and expanding authorities in Syria, it is essential that America's leaders explain to the American public -- and the military in whose name it serves -- the goals and objectives of America's conflicts.