Actually, the Bill of Rights was an outgrowth of the public perception of events surrounding Shays' Rebellion.
The U.S. immigration policy is founded in the principles of Expansionism, which takes as its dictum, "growth is good". On a planet with 7 billion people, there is reason to question that wisdom.
Ideals are worthwhile, but rarely pay the rent, just ask Karl Marx. Policy that is dictated by idealogy most often comes at a very high cost.