One of the biggest clashes in the Republican debate Thursday night came after New Jersey Governor Chris Christie was asked about his past attacks on Senator Rand Paul. The two men disagree about an NSA program that spied on tens of millions of innocent Americans by logging all phone calls they dialed and received. Paul, a leading critic of the phone dragnet, has argued that it flagrantly violates the Fourth Amendment right to be free from unreasonable searches and seizures.

Christie has said that if America is hit by another terrorist attack, Paul should be called before Congress to answer for his efforts to constrain the NSA’s domestic spying.

“Do you really believe you can assign blame to Senator Paul just for opposing the bulk collection of people's phone records in the event of a terrorist attack?” a moderator asked Thursday. The ensuing exchange highlighted stark differences in how the rival candidates would govern and their respective understandings of the Constitution.

Christie stood by his attack.

“Yes, I do,” he said. “And I'll tell you why: because I'm the only person on this stage who's actually filed applications under the Patriot Act, who has gone before the Foreign Intelligence Service court, who has prosecuted, investigated, and jailed terrorists in this country after September 11th. I was appointed U.S. attorney by President Bush on September 10th, 2001, and the world changed enormously the next day. That happened in my state. This is not theoretical to me. I went to the funerals. We lost friends of ours in the Trade Center that day. My own wife was two blocks away, at her office, having gone through it that morning.”

A GOP debate stage hasn’t witnessed such naked exploitation of the emotions surrounding 9/11 since Rudy Giuliani used the same manipulative tactic in 2008. Then, as now, there are plenty of people who stood every bit as close to the Twin Towers as they fell and drew opposite conclusions about how to fight the war on terror. Invoking physical proximity to the attacks is an irrational appeal made to avoid the need for a more substantive analysis. Saying “the world changed that day” does not justify all possible responses.

“When you actually have to be responsible for doing this,” Christie continued, “you can do it, and we did it, for seven years in my office, respecting civil liberties and protecting the homeland. And I will make no apologies, ever, for protecting the lives and safety of the American people. We have to give more tools to our folks to be able to do that, not fewer, and then trust those people and oversee them to do it the right way.” In fact, the phone dragnet has never stopped a single terrorist attack, during Chris Christie’s tenure as a U.S. attorney or at any other time.

For that reason, advocates of the phone dragnet wouldn’t be apologizing for protecting our lives and safety––they would be apologizing for abrogating our civil liberties with a surveillance program that didn’t even make us any safer in the bargain.

More generally, the torture of prisoners, the invasion of Iraq, the worst abuses of J. Edgar Hoover, and all the illegal behavior uncovered by the Church Committee were carried out by a lot of people who had the intent of protecting the lives of Americans. That intent does not excuse imprudent or unlawful acts––and as a federal court has ruled, the provision of the Patriot Act that the NSA and the Obama Administration have used to justify the phone dragnet does not, in fact, even authorize it.

Over the centuries, adhering to the Fourth Amendment  and the rule of law has done far more to protect the lives and safety of Americans than any domestic spying effort. But Christie’s bad heuristics leave him unable to appreciate the lessons of history.

Paul responded to Thursday’s attack by expressing his preference for targeted surveillance rather than an expansive dragnet that sweeps up everyone’s metadata. “I want to collect more records from terrorists, but less records from innocent Americans,” he said. “The Fourth Amendment was what we fought the Revolution over! John Adams said it was the spark that led to our war for independence. I'm proud of standing for the Bill of Rights. I will continue to stand for the Bill of Rights.”

Christie was ready with a retort.

“You know, that's a completely ridiculous answer: ‘I want to collect more records from terrorists, but less records from other people.’ How are you supposed to know?” Like Keith Alexander, Christie seemed to be arguing that the government needs to intrude on everyone’s private communications to identify terrorists. It’s the logic of general warrants. How can the police know who is keeping an illegal gun in their home without searching the contents of everyone’s home? Republicans uncomfortable with that logic should avoid voting for phone dragnet supporters.

“Get a warrant!” Paul said. “Get a judge to sign the warrant!”

Christie did not engage on warrants.

“Listen, Senator, you know, when you're sitting in a subcommittee, just blowing hot air about this, you can say things like that,” he said. “When you're responsible for protecting the lives of the American people, then what you need to do is to make sure––to make sure that you use the system the way that it’s supposed to work.”

In fact, “get a judge to sign a warrant” is a rather succinct description of how “the system” is “supposed to work,” if we define “the system” as the Constitution rather than national-security officials following their gut instincts. It’s hardly “blowing hot air” for a senator to call on the executive branch to follow the law.

“Here's the problem, governor,” Paul said.  “You fundamentally misunderstand the Bill of Rights. Every time you did a case, you got a warrant from a judge. I'm talking about searches without warrants, indiscriminately, of all Americans' records, and that's what I fought to end. I don't trust President Obama with our records. I know you gave him a big hug, and if you want to give him a big hug again, go right ahead.”

Rather than articulate why he believes individualized warrants are neither lawfully required nor prudent, Christie chose to address the “hugging Obama” part of the argument. “And you know—you know, Senator Paul? Senator Paul, you know, the hugs that I remember are the hugs that I gave to the families who lost their people on September 11,” he said. “Those are the hugs I remember, and those had nothing to do with politics, unlike what you're doing by cutting speeches on the floor of the Senate, then putting them on the Internet within half an hour to raise money for your campaign, and while still putting our country at risk.”

That might be the strangest part of Christie’s answer. There he was, standing on a stage full of candidates who spend much of their time begging rich people for campaign cash. And yet, the single  fundraising tactic that Christie chose to disparage was the comparatively pristine, democratic tactic of putting one’s senate speeches online in the hope that regular citizens will like what they say enough to donate money.

Isn’t that how campaign finance ought to work?

On Fox News after the debate, a couple of commentators suggested that Christie won his exchange with Paul. I cannot comment on the style preferences of a GOP voter base that presently prefers Donald Trump to all other candidates. But on substance, Paul easily bested Christie in this exchange. Granted, I already agreed with his opposition to the phone dragnet. But even apart from that, when one candidate says policy x violates part y of the Constitution and a rival responds that he saw the Twin Towers fall and has hugged lots of survivors, identifying the more rational man isn’t hard.

Christie seems oblivious to the basic logic of the Bill of Rights. The constraints it places on government are not suspended in the aftermath of a terrorist attack––they are, in fact, most important precisely when a polity is panicked and officials are unusually able to seize excessive power without criticism. His praise for leaders unapologetically jettisoning such constraints in the name of protecting us is more dangerous than any terrorist plot in U.S. history.