Earlier quoted context omitted.
You do not. We have this thing in our constitution called the 5th amendment. You cannot be forced to divulge the contents of your mind, including your pin or passwords. Case law supports this. For US citizens at least. Hopefully the constitution is still worth something.
You're forgetting about the Constitution-Free Zone within 100 miles of all points of entry including international airports that covers essentially all of the 48.
There is a separate border search exception at the point a person actually enters the country which does allow searches of electronic devices. US citizens entering the country may refuse to provide access without consequences beyond seizure of the device; non-citizens could face adverse immigration actions.
To be clear, I do think all detentions and searches without individualized suspicion should be considered violations of the 4th amendment, but the phrase "constitution-free zone" is so broad as to be misleading.