On 17 September 1787 the Constitution of the United States was signed by the delegates of the convention meeting in Pennsylvania. It would be many months of long debate before the Constitution was ratified.

American military officers are perhaps unique in their sworn allegiance not to their commanders, and not to the President, but to the US Constitution:  

I…do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign or domestic, that I will bear true faith and allegiance to the same…

Though amended through time, the US Constitution represents both the founding and continuation of a free nation without peer in the world.

Today is Constitution Day, the federally recognized day that recognizes the signing by the Convention of the US Constitution on 17 September 1787.

Have you read the document you have sworn to defend?  You can do so for free online (and view the one on display in Washington or get the Kindle version for free), or you can even buy your own pocket copy.  Might be time to refresh your memory.