Politico reported Monday that Trump uses at least two iPhones. One is just for making calls, and is regularly swapped out, although unlike the super-secure phone used by President Barack Obama, it has a microphone and camera.

The mic and camera might enable surveillance, but it’s the second phone that may be a particular issue. This is the one Trump uses to tweet: it apparently has nothing on it but Twitter and a few news sites.

According to the Politico piece, Trump has rebuffed his aides’ attempts to have him swap out the Twitter phone on a monthly basis, as protocol demands, because doing so would be “too inconvenient.” He has apparently gone as much as five months without changing the device.

A West Wing official told the publication that regular swaps are not needed “because of the security controls of the Twitter phone and the Twitter account,” adding: “Due to inherent capabilities and advancement in technologies, these devices are more secure than any Obama-era devices.”

Almost every national security official polled by Politico said phones remain vulnerable to hacking and surveillance. “It’s baffling that Trump isn’t taking baseline cybersecurity measures at a time when he is trying to negotiate his way out of a trade war with China, a country that is known for using cyber tactics to gain the upper hand in business negotiations,” said Samm Sacks of the Center for Strategic and International Studies.

Trump reluctantly surrendered his Android phone upon assuming office, due to the security concerns of those around him.

But how secure is the iPhone? It is certainly the case that forensics companies such as Israel’s Cellebrite claim the ability to hack into Apple’s devices due to knowledge of hidden bugs in them, but that hacking requires physical access to the phone in question.

There is no publicly known way to remotely hack into an iPhone. However, that doesn’t mean it’s impossible—and if anyone does know how to do it, it would probably be the Russian or Chinese intelligence services. And if they can get into it, there may be a lot to learn about the U.S. president’s whereabouts and—if he uses Twitter’s direct messaging feature—his communications.

If nothing else, imagine the chaos that could be achieved by having Trump’s Twitter account broadcast belligerent, embarrassing messages that undermine U.S. laws and policy.