Arick Wierson is an Emmy Award-winning television producer and former senior media adviser to New York City Mayor Michael Bloomberg. He currently advises political and corporate clients in the United States, Africa and Latin America. You can follow him on Twitter @ArickWierson . The views expressed in this commentary are his own.

(CNN) I have known Kirstjen Nielsen for nearly 30 years -- since we were both incoming freshman at Georgetown University's Walsh School of Foreign Service, or SFS, in Washington. The program is considered to be a training ground for the diplomats, policymakers and global business leaders of tomorrow. As the school's website says , "SFS undergraduates enter a prestigious program with a legacy of academic excellence combined with a devotion to humanitarian service."

But I, like many Americans, watched in horror as Nielsen, now our nation's Department of Homeland Security secretary, attempted to defend the indefensible at Monday's evening press briefing aimed at defusing the swelling chorus of voices shocked by the images and sounds of children -- some just a few months old -- being torn from their parents' arms by US border security officials.

So much for humanitarian service.

CNN's Chris Cillizza nailed it when he summed up Nielsen's robotic performance at the podium in the White House Briefing Room: "This issue isn't just about dry policymaking. It's about people, too. And Nielsen never even nodded to that fact."

Something just doesn't sit well with the image of a bureaucrat scoffing at a reporter's question about whether separating young immigrant children from their parents constitutes a form of child abuse.

But Kirstjen Nielsen should know better than to attempt to reduce a crisis as visceral as this one to statistics and wonkish D.C. policy-speak -- especially when it is a crisis of the administration's own making and all part of an elaborate sham aimed at pleasing her boss, the President, who sees the children caught up in this drama not as human beings, but as mere negotiating chits in a game of brinkmanship with a Congress that doesn't want to give him his "wall."

At Georgetown, Nielsen and I sat in many of the same classes, including the de rigueur freshman theology class -- taught by a Jesuit priest -- in which we read the works of Catholic luminaries such as St. Thomas Aquinas, the medieval Italian theologian, who taught that "good is to be done and pursued and evil avoided ... for the common good."

If forcibly separating children from their parents -- themselves seeking safe haven from countries ruled by violent gangs and cartels -- and placing them in cages upon arriving in the United States isn't the definition of evil, I would be hard-pressed to define what evil might be.

Back then, Nielsen was what today we might call a compassionate conservative; she was a Republican, for sure, but of the Bob Dole ilk. She was smart, sure of herself, and unafraid to stake out strong positions. But she was also measured and seemed to grasp the nuances that complex questions often engender.

Privately, many of us who know Nielsen from Georgetown cannot believe that she is the same person who we see as, if not the architect, then certainly the engineer of this tragically dark chapter of our nation's history. "How does she bring herself to do this?" questioned one mutual friend in a recent group chat among several SFS alums.

The issue is that among those of us who know her, we can be fairly certain that Nielsen hates this policy and hates defending it, but she feels that in the oddball "Game of Thrones"-like environment of the Trump presidency, she was handed an opportunity to land a Cabinet level position -- one that she might not have gotten in any other administration. For Nielsen, her reasoning for staying on and pretending to defend the policy could be quite simple: This is the most important role she will ever hold in her life, and to give it up after just a few months on the job would be asinine.

But Nielsen needs to think this through more than one chess move ahead. If we have learned anything in the past year and a half of the Trump presidency, it is that Donald Trump never takes responsibility or blame for anything. As this crisis at the border grows in scale and magnitude, and as his claims that this is all the " Democrats' fault " fail to stick anywhere outside of far-right media, Trump will look for a new scapegoat -- and there is none more obvious than his arguably underqualified secretary of Homeland Security. That clock is already ticking.

If there is but a scintilla of good left in Kirstjen Nielsen's soul -- and we who have known her for several decades think there is -- she has only one good option and that is to resign her post as secretary of Homeland Security, a move suggested Monday afternoon by California Sen. Kamala Harris.

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If Nielsen were to resign, it would be a powerful blow to Trump's zero-tolerance strategy at the border, by effectively throwing the onus of the unpopular policy back squarely into the Oval Office. An acting homeland secretary would take the reins of a highly toxic policy, while Trump is forced to search for yet another Cabinet level position. The ensuing confirmation hearings would essentially become a congressional referendum on Trump's border and immigration policies, subjecting American living rooms to days, if not weeks, of torrid, heartbreaking stories of children being yanked from their parents' clutches being read aloud in congressional chambers.

But Trump is smarter than that -- he would use Nielsen's departure as an excuse to halt or revert the family separation policy. Nielsen, instead of going down in the annals of the Trump presidency as an enabler of actions that have been compared to World War II Japanese internment camps, could emerge as the heroine of this crisis, falling on her own sword for the good of the more than 2,000 children who don't have a father or mother nearby to console them and for the moral compass of an entire nation.

Kirstjen, think about it.