More or less grew up within walking distance of the Rio Grande near Del Rio, Texas in the 50’s. Several uncles were Border Patrol “River Riders” who were well armed and spent a week at a time patrolling the river, alone. River Riders were a lot like the 1800’s Texas Rangers in Lonesome Dove. Don’t remember hearing much about them bringing in prisoners.
Even in a rural area close to the Rio Grande, rarely saw any illegals.
The deep insertion re-patriation process probably had a strong effect, plus illegal jobs dried up AND no welfare all helped cut the flood to a trickle.
I think one reason Ike was able to get by with Operation Wetback was due to USA’s fresh memories of Mexico being pretty damn friendly and sympathetic with the Nazis during WW2.
As soon as the damn dems got back in power all that rapidly changed, especially under Landslide Lyndon.