I can remember Bill Jordan and seeing him on tv “What’s My Line or To Tell the Truth”! Big man with a fast draw. He shot aspirins with a Model 19 revolver in 357. He worked for the Border Patrol when it wasn’t open borders and “Welcome Wagon” duties. The border was protected and the BP fought criminals- smugglers and the like and shootouts were frequent. It was a dangerous occupation.
The Border Patrol was formed in 1924.
Buck Newsom and Bill Jordan were agents* when you had to have some grit in your craw.
Prior to that, the Tex/Mex border was "protected" (such as it was) by the Texas Rangers. Also a bunch that was pretty rough. It was once a belief that most (?) Texas Rangers were recruited from the other side of the badge. From stories about them, I don't doubt it!
* - Obama combined Customs (blue uniforms) with the Border Patrol (green uniforms) to form the CBP (Customs & Border Protection).Those green uniforms have no love for the blue uniforms.....and vice versa!