Given the international terrorist and criminal threat to the U.S., National defense requires full control of the strategic southern border to prevent crossing except at controlled entry points where the legality of crossing can be determined.
Controlling that border is a fundamental Constitutional duty of the Federal government to defend the Nation from persons with intent to harm the U.S. and its citizens, independent of immigration policy.
Complete, double physical barriers with border patrol observation should be the primary means of controlling the border.
Just as the U.S. did not land astronauts on the moon immediately after President Kennedy announced that goal, a barrier to illegal border crossing requires long-term funding and construction. It must be started now and completed.