As news trickled out that Tuesday's horrific tragedy in New York City, in which a man used a rental truck to kill eight people on the West Street bike path, appears to have been an act of terrorism inspired by ISIS, Donald Trump wasted no time in using the incident as a segue to promoting the relevant pillars of his policy agenda.

Given the president's reluctance to discuss legislative responses in the immediate aftermath of, say, the Charlottesville terrorist attack, or the apparently-random shooting in Colorado on Wednesday night that left three more dead, it's hard to interpret his sudden intense interest in the crime committed by an immigrant as anything other than transparently exploitative. But upon learning that the rental truck driver had asked to display an ISIS flag in his hospital room, Trump moved quickly from his usual brand of passive xenophobia to criminal justice expert.

Trump also took the time to inform the world that he "would love" to have the suspect stand trial before a Guantanamo Bay military commission, but that he had elected to keep the case in the domestic courts in the interest of expeditiously achieving justice. "Should move fast," he said, reiterating his earlier all-caps argument in case there was any remaining ambiguity. "DEATH PENALTY!"

Donald Trump has become so adept at dispensing with norms that it can, on occasion, be difficult to identify each and every time it happens. But a sitting president weighing in on the outcome of a specific criminal case—one in which charges hadn't even been filed at the time of his tweets—is appalling. One of the most important implications of this country's system of divided government is that justice is administered to individuals according to the law, not politics. Yes, I realize that the system is imperfect, but the structure—in which, at the federal level, innocence and guilt are determined by independent judges and not elected officials with partisan agendas—is so engrained in Americans' understanding of how government works that we often take it for granted. (Imagine, for example, if one of the commander-in-chief's formal job duties were adjudicating criminal cases. You would probably find this alarming.)