Breaking the encryption abilities of large tech firms like Apple would hurt U.S. national security, according to former CIA director Michael Hayden.

In an interview with Fusion, Hayden, who also ran the National Security Agency during George W. Bush’s administration, said that the FBI’s request to add a backdoor to tech devices that would enable law enforcement to access sensitive information would inevitably lead to exploitation by foreign powers.

“I think this is a close but clear call,” he said. “The Director of National Intelligence [James Clapper] has said the greatest threat to the U.S. is cyber,” he said. Breaking encryption “will fundamentally weaken it’s architecture…And what do you do when the Chinese come to Apple for what they view as a legitimate national security threat?”

Hayden is promoting his new book, “Playing to the Edge: American Intelligence in the Age of Terror,” in which he recounts his time leading America’s clandestine agencies. He told Fusion that he has no regrets about any of the decisions he made as NSA and CIA director, including torture. “At the time, I understood that I would have to live with these decisions one, five, ten years later,” he said.

And he is alarmed at the current state of debate found in the presidential campaign, saying rhetoric around national security “had sunk below what you’d find on a bumper sticker.” He has found Donald Trump’s remarks about killing terrorists’ families particularly troublesome.

“It’s illegal, it’s unethical, and operationally it’s a really bad idea,” he said. “The moment that order gets to a service member in uniform, it will be disobeyed.”

He also blasted Trump’s proposal for banning all Muslims from entering the U.S.

“Our enemy is trying to tell the rest of the Muslim world that there is undying enmity between Islam and the West. That is simply not true, and we need to push back against that,” he said. “It’s really hard to push back against when a leading presidential candidate says we should close our border to all adherents.”

Watch the full interview below: