It’s never a good sign when you have to declare during a debate that “I really am not a maniac.”

But that’s what FBI director Jim Comey found himself saying in advance of his testimony to the senate on Wednesday where he once again argued that tech companies need to figure out a way to install backdoors in all their communications tools so that there’s never an email, text or phone call that the US government can’t get its hands on.

Ever since Apple commendably announced last September that it would increase the security protecting millions of iPhones so that only the user - and not the company - would be able to unlock them, Comey has spent months arguing that this could spell disaster for the FBI trying to access what is on suspects’ phones. Since then, other popular messaging services like WhatsApp have followed in Apple’s footsteps and encrypted user’s chats “end-to-end.”

Since his initial objection to tech companies enabling end-to-end encryption, Comey has rightly been bombarded with criticism from security experts, cryptographers and engineers, who have at various times called his backdoor proposal technically impossible, an enormous setback for cybersecurity, an invitation for countries like China to mandate the same, potentially devastating to the economy and not needed. (Comey admitted Tuesday he has no specific data to back up his claim that encryption has prevented the FBI from solving crimes.)

Notably, just one day before Comey’s testimony, an all-star group of leading technical experts released a paper running through, in specific detail, the myriad of problems mandated backdoors in encryption would cause for the public. The paper posed dozens of technical questions about how such backdoors would work in practice, which the FBI has so far not even attempted to answer. The scale of the questions – and the fact that many of them will never have clear answers – shows just how ill-thought out the FBI’s idea really is.

The criticism seems to have forced the FBI to scale back its ambitious and dangerous rhetoric. Comey kept emphasizing Wednesday that he “was not an expert,” does not prefer a “one size fits all” law anymore, and that he wanted to work with tech companies – so they weaken our security voluntarily. He also claimed he doesn’t want the government to hold those master keys to everyone’s communications, he just wants companies to hold them and hand over data to the government when asked.

But no matter who holds the keys, the same problems persist. The FBI – and apparently many senators, judging by Wednesday’s hearings – think that all you need to do is force a bunch of smart people to get into a room and they’ll be able to wave their hands to magically to solve one of the hardest unsolved problems that has vexed computer engineers for decades.

Here’s a question for the FBI director – or UK Prime Minister David Cameron, who is pushing a similar proposal in Britain – which no one seems to ask: can you name a single security engineer or technical expert who thinks this is even remotely a good idea? So far those experts have universally lined up against it. If Comey is really interested in a debate, he should bring in a technical expert to argue the case, instead of throwing up his hands every time the conversation starts veering into specifics.

The entire premise of the debate that the FBI is “going dark” and can no longer read the communications of criminals – which they have been claiming for 20 years, by the way – is false, as the law professor Peter Swire later told the same senate panel. We are living in “the golden age of surveillance,” Swire argued, and we can look no further than the countless stories about NSA mass surveillance that have come out in the past two years, which by the way, could not be done without the FBI’s close assistance.

Comey says all he wants is a “debate” about the issue. Well, we’ve had the debate. We had it for 20 years. The debate is over – embrace encryption to protect our security. Don’t outlaw it for marginal gains at the expense of everyone.