Officials identified the suspected attacker as Sayfullo Saipov, a legal permanent resident of the United States who arrived in the country from Uzbekistan in 2010 through a diversity visa program. They said Saipov was influenced by the Islamic State, also known as ISIS, and its violent tactics after coming to the United States.

Asked about the suspect Wednesday, President Trump called him an “animal.” Prompted to say whether he thought Saipov should be sent to the detention facility at Guantanamo Bay, Cuba, Trump said, sure, he’d consider it. Later, at Wednesday’s White House press briefing, Sarah Huckabee Sanders said flatly that the White House considered the suspect an “enemy combatant.”

The president also said yesterday that the American justice system (presumably including his own Justice Department) is a “joke” and a “laughingstock.” He further opined, “We also have to come up with punishment that’s far quicker and far greater than the punishment these animals are getting right now,” Trump said. (Terrorists are subject to the death penalty, so it’s unclear what he had in mind.) “They’ll go through court for years … We need quick justice, and we need strong justice,” he said.

Trump was not the only one calling for labeling Saipov an enemy combatant. Both Sens. Lindsey O. Graham (R-S.C.) and John McCain (R-Ariz.) did so as well.

Thankfully, the Justice Department, like the Pentagon, has learned when to ignore Trump. On Wednesday, Saipov was charged in federal court. By Thursday morning, Trump was backing off his support for sending Saipov to Guantanamo. Once again, the ignorant president shot from the hip and had to creep back to reality.

Just how harmful were Trump’s statements? It is reprehensible for the president to defame our justice system, which is not a “joke” nor a “laughingstock” but the envy of the world. Moreover, in the terrorist context, it has proved remarkably efficient in trying and convicting terrorists, and then handing out maximum punishments. The surviving Boston Marathon bombing defendant was convicted in just this way and sentenced to death.

As to the merits of the enemy combatant designation, none of these Washington players seemed to know what they are talking about.

With regard to interrogation under the public-safety exception, a terror suspect can be questioned at length without receiving a Miranda warning. The need to find possible accomplices and other devices, it has been ruled, allows questioning before a Miranda warning is required. Moreover, a Miranda warning is only needed if you need the suspect’s statements to convict; here the evidence of the crime is overwhelming. In short, needing to get as much as information as soon as possible is no reason to declare him an enemy combatant.

As for detaining him as an enemy combatant, the administration would  run into constitutional, legal and common-sense problems. First, it is not clear — and has never been litigated — that the 2001 Authorization for Use of Military Force would apply on U.S. soil to a legal resident, and if it did, whether that would pass muster under the Constitution’s Fifth Amendment due-process protections. Moreover, the issue as to whether the 2001 AUMF drafted with al-Qaeda in mind now applies to the Islamic State is an open one. Nor is it clear that Saipov, who seems to have visited terrorist websites but not received direction, would qualify under the AUMF, even if it could be applied to the Islamic State. If you wanted years of litigation, you’d go down this road, creating a field day for constitutional lawyers.

Moving to the common-sense concerns, why in the world if you are looking for quick, tough justice would you go to a nonpunitive military commission system that has managed to convict just a handful of people since in 2001, and would, in any event, be obligated to release the suspect when hostilities cease? If you want quick, tough justice, I can think of no better option than a federal court in New York City. Unlike with the 9/11 hijackers, there are unlikely to be any national security secrets that we would want protected. Because he may be a lone wolf, Saipov could be treated no different from any other suspected felon with appropriate security for the courtroom and protection for jurors.

When Trump pops off about the defects of our justice system with no understanding of what he is saying, he underscores his unfitness and undermines one of the great jewels of American democracy, the court system. For Trump to slander the courts as a “joke” gives aid and comfort to our enemies (both terrorists and thug-ocracies such as Russia). It is a regrettable but natural continuation of his indefensible slurs about “so-called judges.” Unfortunately, Republicans have been too cowardly to take him on, even rhetorically on this point. Nevertheless, one cannot ignore his unwillingness to defend the Constitution, of which courts are a part, in blatant disregard of his oath. His meek retreat this morning underscores just how ignorant he is — and how willing to make irresponsible assertions.

Based on today’s tweet, we were right to assume that neither Trump nor Sanders had any idea what he/she was talking about (always a good assumption). We will watch with pride as American justice takes its course — and with horror as Trump continues to wreak havoc from the Oval Office.