In a new Frontline documentary, a Border Patrol agent describes taking part in a\u0026nbsp;pilot program to separate families\u0026nbsp;nearly a year before the Trump administration officially unveiled the policy—saying that while he was unhappy about separating children from their parents, he and other agents were following orders.Journalist Martin Smith interviews agent Wesley Farris in \u0022Targeting El Paso\u0022 about the program Farris worked on in the summer of 2017 in El Paso, Texas. Agents were instructed to separate families as the administration tested the theory that doing so would deter people from trying to enter the U.S. at the border city.\u0022That was the most horrible thing I\u0026#039;ve ever done,\u0022 Farris tells Smith in an excerpt released ahead of the documentary. \u0022You can\u0026#039;t help but see your own kids.\u0022Farris describes one experience in particular which caused him to ask his supervisor to take him out of the pilot program.\u0022It was a young boy. I think he was about two. The world was upside down to that kid,” Farris says. \u0022So when the contractor tried to take him away, he reached for me and he climbed up on me again, and he was holding on to me. So that that one got me a little bit.\u0022\u0022I said at that one, \u0026#039;I\u0026#039;m not doing this anymore. I won\u0026#039;t do it,\u0026#039;\u0022 he tells Smith. \u0022I went back to the supervisor and I told him, \u0026#039;Don\u0026#039;t assign me to do that anymore.\u0026#039;\u0022Farris \u0022wanted to\u0022 take his complaint up the chain of command, he says, but the Border Patrol agents who were separating families were required to do as they were told.\u0022I mean, none of us were happy about it,\u0022 Farris says. \u0022We were all told to do this.\u0022Journalist Brooke Binkowski suggested in a tweet that Farris\u0026#039;s defense mirrored that of numerous war criminals who have invoked the \u0022Nuremberg defense,\u0022 infamously used by Nazi official Adolf Eichmann in the Nuremberg trials after World War II.\u0022So he was just doing his job? Where have we heard that defense before?\u0022 tweeted Binkowski.\u0022“I mean, none of us were happy about it,” Farris says. “But everybody around me was just doing exactly what… We were all told to do this.”\u0022Ah, so he was just doing his job? Where have we heard that defense before? https://t.co/VdG2sXEQ2G via @frontlinepbs— Brooke Binkowski (@brooklynmarie) January 7, 2020The Trump administration announced six months after the pilot program ended that it would begin separating families on a much larger scale, eventually separating more than 5,000 children from their parents or guardians at the border.As the program rapidly drew international outrage in the summer of 2018, then-Homeland Security Secretary Kirstjen Nielsen scoffed at the suggestion that the administration was separating families as a deterrent to asylum-seekers and migrants—but \u0022Targeting El Paso\u0022 presents new evidence that it was doing just that.\u0022It aligned with my experience, in the times where we applied a consequence to people who cross the border illegally, we got less of them crossing the border illegally,\u0022 Ronald Vitiello, former acting director of U.S. Immigration and Customs Enforcement (ICE), tells Frontline. \u0022And so when zero tolerance is discussed as a way forward, we knew that it was going to be a benefit to us.\u0022\u0022Targeting El Paso\u0022 will premiere on PBS stations on Tuesday evening.