And this is a town that everybody agrees, law enforcement, Border Patrol, residents on both sides, is a staging area of illegal drugs and illegal aliens.
This town is in the middle of the USA. 
It is on the Border because Border Patrol is involved. 
( z1 be-located-at :ARG1 ( z2 town :mod ( z3 this ) ) :ARG2 ( z4 middle :part-of ( z5 country :name ( z6 name :op "USA" ) ) ) )