There are a handful of state courts in the US that find passwords testimonial, and therefore the Fifth Amendment prevents compelled production of passwords. [1]
Actually, the First Congress okayed border searches. Given that many of them were authors of the Constitution, it stands to reason that border searches were always intended to be allowed under the Constitution, even if not stated explicitly.
I also suspect they did not anticipate it being both feasible and normal to have one’s entire private writings on one’s person at all times like modern phones permit.
Could that apply here?
1 https://www.techdirt.com/articles/20191124/09372943445/penns...