Most walls in the Pentagon are covered by elaborate decorations, but the decoration of the River Entrance staircase is perfect in its utter simplicity. In my mind it’s far more significant than any other decoration in the building; it’s a complete and unassuming expression of the purpose and meaning of military service.

The River Entrance itself is reserved for high-ranking officers, senior officials, and staff members who are traveling with “the boss.” Next to the River Entrance, on the ground floor, is the office of the Chairman of the Joint Chiefs of Staff. Above the entrance, on the second floor, is the office of the Secretary of Defense. And right across from the entrance, a staircase leads to the Secretary’s corridor.

My former office at the Pentagon is on the ground floor, so I used the River Entrance staircase to deliver speeches to Secretary Panetta. On my way up the stairs, I often took a moment to look at the decorations on the wall. I imagine that Secretary Panetta did the same thing from time to time.

At the first landing, there’s a framed copy of the military Oath of Office:

I do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion, and that I will well and faithfully discharge the duties of the office on which I am about to enter. So help me God.

On the wall leading to the second landing, raised black letters spell the Preamble to the Constitution:

We the people, of the United States, in order to form a more perfect Union, establish justice, insure domestic tranquility, provide for the common defense, promote the general welfare, and secure the blessings of liberty to ourselves and our posterity, do ordain and establish this Constitution for the United States of America.

And at the second landing, there’s a framed copy of the Declaration of Independence (excerpted here for brevity).

…We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable rights, that among these are life, liberty, and the pursuit of happiness – that to secure these rights, governments are instituted among men, deriving their just powers from the consent of the governed…

I like to consider the progression of these passages from top to bottom, as you might encounter them walking down the staircase – or as Secretary Panetta saw them on his way home from work.

First, he saw the Declaration, which asserts the basic purpose of any government (shifting the words around: to secure unalienable human rights to life, liberty, and the pursuit of happiness). Next he saw the preamble, which lists the aims of our government, one of which is to provide for the common defense. And last, he saw the oath of office for military service members, who swear to support and defend the Constitution of the United States against all enemies, foreign and domestic…

The act of reading the passages in that order (and all at once) creates a logical progression of ideas; it offers the surest way to see the direct connections between the Declaration, the Constitution, and the Oath; and it signifies the fundamental purpose of the military and its role in our country.

The Pentagon is a big place, but for me the River Entrance staircase is the very soul of the building…