What Happened To The Precept Love Your Neighbor As Yourself

I am having a disagreement with several parties that the ideals behind the Declaration of Independence and the Constitution are love your neighbor as yourself. The whole ideal of natural rights is based on two premises. The first is if you posses something or have the ability to do something you have the right to posses it or do it. The second is that you are limited by the law love your neighbor as yourself. From those two precepts the whole Natural law mention in the declaration and given power in the Constitution gains its justification. The fact I debate this with individual from both the left and right political spectrum shows how far the United States has departed from the ways of its youth. It is obvious that religious and government organizations are failing in their duty to teach people to love one another. This explains the decline of western civilization because without civilized behavior civilization is doomed.