Is it cost effective to spend millions of dollars in an effort to stop a hand-full of people″ who are bound to terrorize the United States? What is NAFTA and GATT ?

Is it cost effective to spend millions of dollars in an effort to stop a hand-full of people″ who are bound to terrorize the United States? What is NAFTA and GATT ? How have they changed throughout Presidential Administrations? 2) What is the ″Hardened Border Paradox? What is the ″Open Border Paradox? How can both be overcome?