Steve Schneider (Paul Sparks) was introduced to the teachings of David Koresh (Taylor Kitsch) in 1986, while he was still living in Hawaii and working toward his Ph.D. at the island's state University. Steve tried to “detect flaws and inconsistencies" in David's scriptural system, and even arranged for Koresh to debate bible interpretations with a professor colleague of his. Soon after, Schneider became one of Koresh’s most faithful followers and closest confidant, even going as far as to manage his Messiah’s band. The two became inseparable.
Koresh chose Steve's wife, Judy (Andrea Riseborough), to be one of his brides, and fathered a child in Schneider's place (who, according to Waco, may have been impotent). The men who followed David into the Branch Davidian cult were not allowed to have sex, even if they were married. Carnality was viewed as an indulgence of the flesh; a sinful act that had to be rejected absolutely. David and Judy's daughter, Mayanah, was a healthy girl who grew up in the Mount Carmel compound until the siege claimed all four of their lives on April 19, 1993. It was a dysfunctional familial unit that literally ended in flames.
Although he obeyed his shepherd, Steve harbored deep-seated issues regarding Mayanah’s conception. As he proclaims to David Thibodeau (Rory Culkin) at one point: “We were lovers for close on twenty years, married for ten, and never made a baby. Now suddenly, she’s having his child!” Sparks does a great job (with his Midwest-tinged twang) of conveying not only Schneider's discomfort with willingly giving his better half to another’s hand out of blind faith, but also Steve's own perceived inadequacies as a man. One doubt fuels another belief, as it's not hard to see Steve wondering if God rendered him incapable of making a baby with Judy as a sort of predestination. Maybe his malfunctioning manhood was all supposed to be part of bringing his Messiah's child into this world?
Following "Operation Showtime", Koresh is gut-shot and dying, leaving Steve to lead the compound. Schneider attempted to negotiate with the FBI and ATF during the Waco siege, bringing a calmer voice of reason to the proceedings than David’s seemingly paranoid notions that the government was simply going to tear them all down (which, in fairness, they did end up doing). Steve reasons with lead negotiator Gary Noesner (Michael Shannon), explaining that he isn't exactly sure what the Davidians even did to warrant this militaristic presence (by Day 3 of the stand-off, tanks were on Mount Carmel's front lawn). Tensions have run so high that the nursing mothers inside the compound can no longer produce milk, and Steve requests that the FBI ship some in. In return, Gary asks that the cult show a sign of good faith and release a handful of the children; a demand that Steve struggles to get anyone else to agree to.
However, Steve's level-headed presence allowed for a deal to be cut, even as the FBI publicly (via television news broadcasts) try to paint the Davidians as uncooperative. The government says that they've desperately tried to bring milk to these starving children, but the Branch has turned them away, time and again. Both Steve and Gary know this isn't true, and Gary understands (but certainly won't tell Schneider) why these lies are being spun at the expense of negotiation tactics: the whole event is at least partially a PR stunt for the ATF to regain face following the tragedy at Ruby Ridge. Again, Schneider finds himself putting his trust in an institution that may not have his best interests at heart. Sparks paints a rather fascinating portrait of a man serving several masters, but never himself. He wants everyone to live in peace, but we know that simply is not a goal that can be accomplished in this situation.
Waco's fourth episode - "Of Milk & Men" - ends with the power being cut in the Mount Carmel compound by the FBI, even after Steve successfully talks David and the rest of the Branch into releasing some of the sect's children as a sign of good faith (but not Judy and Mayanah, of course). This comes after Koresh releases a self-made video to Noesner, explaining the human interest behind their struggles to survive as children of God inside the system of man's law. The recording is quickly confiscated by Noesner's superiors, saying they can't ever let the general public see it because "it'd make them look too normal." In the end, it never mattered what Steve, or David, or Gary, or anyone inside Mount Carmel thought or wanted. David Koresh and his followers were only going to come out on the FBI's terms; a forceful trap of " bad faith" that Schneider couldn't help but fall into, just as he had with David's magnetic spiritual spell.