You're not the only one wondering this, and there's a related lawsuit (on first amendment grounds).

https://www.politico.com/story/2018/10/01/trump-presidential...

Because the 2006 law authorizing this mandated that Presidential Alerts not be able to be disabled.

https://www.congress.gov/109/bills/hr5785/BILLS-109hr5785ih....

With a little effort you can. Some ADB creativity with a restore rom or rooting or magisk. You'll be hunting down settings inside /data/data/com.android.messaging/shared_prefs/com.android.messaging_preferences.xml

It may have a different name as phone manufacturers like to play around with what they name it, and each setting may have a different specific name. Each phone may have a different term for it, but you'd be hunting for 'presidential', or something like 'pref_key_cmas*' and setting that to false.

on the iPhone there's a setting for "Emergency Alerts" at the bottom of Settings -> Notifications.

edit: apparently "Presidential" alerts will override this setting, so I guess you can't disable it after all.

Presumably they'd be used for FEMA-type issues; which are generally about imminent hazards.

Ridiculous, presidential Spam...

It's supposed to be for extremely serious situations only. If the bombs are going to start falling in five minutes, millions of lives could depend on everybody getting the word as soon as possible. An unskippable alert pushed out to every cellphone in the country is the best way in the modern age to ensure that happens.

As long as its use is restricted to only that kind of sky-is-falling situation, I don't have a problem with being unable to opt out. If Trump starts using it to advertise his latest rally, that would be an abuse of the system and pressure to let people opt out would start piling up rapidly.

Probably because Google and Apple make essentially every phone in use and they agreed to ignore your settings in favor of the President's.

I guess the benefit of not having control is that you can't be accused of being a jerk for having it go off during a movie or in court or whatever, since you have no choice.