Border searches are complicated because there's a good deal of conflicting, ambiguous, and overly broad laws at work there.
- US citizens cannot be denied entry BUT they can be searched, harassed, threatened, delayed, and of course arrested if they have active warrants
- they can confiscate and hold anything you have with you, and they've got a fist-full of catch-all reasons that they can abuse to allow them to apply that to anything, including the clothes on your back.
- they can make it nearly impossible to get legal property back if they set their mind to it. The bag of tactics to delay return of property is deep, and the more you refuse to comply with their "requests", the harder they can make it to get your property back. Saying "they can't keep it FOREVER" doesn't mean much in practice when they can take months or YEARS to return it, and even then only after an expensive legal fight. (and that's if they don't "lose" it in the process) They're well-known to delay or ignore court orders, and unfortunately judges seem reluctant to use the court's authority to force them to follow the court orders. Just look at the hundreds of court orders they've defied, compared to the ZERO arrests that have been made for such defiance. You and I can't get away with that, but they can, and they KNOW they can, so they're really not worried about consequences if they ignore a court order.
- when (legally) detained at the border, destruction of property is a crime. The courts are going to have to work out the specifics, but a big part of it is going to hinge around whether or not giving someone a duress password can be considered "destruction of evidence". He's not the one that typed in the password, and that is what destroyed the evidence. I personally think he should have just kept his mouth shut, and used the shortest possible duress password that's early in the "try all combinations" search list like AAAAAA or "letmein". The "destruction of evidence" law was written long before duress passwords existed, so a judge is going to have to decide whether or not the law is broad enough to cover them. I foresee them comparing a duress password to an incinerator trap placed inside a safe, that if you try to drill the safe, the incinerator turns on and turns the documents into charcoal before you can get the safe open. Usually in a case like this, the prosecution has to show some proof or at least strong likelihood that there was damning evidence in the safe. If they meet that bar, the court/jury is allowed to infer that the destroyed evidence "would have been harmful to their case". But I haven't heard any mention of any specific crimes, it looks like this was a "fishing expedition" on his phone. And courts REALLY don't like fishing expeditions. If all they can say is "we strongly suspect there was evidence that SOME law was broken on the phone", that won't meet the legal standard. It's not a legal search unless you can specify in detail WHAT you are looking for.
- the border people clearly screwed up in actually providing an obviously fictitious reason for his detention. That's definitely going t be used as part of his defense, because if the detention wasn't done legally, then the "destruction of evidence during a lawful search" is going to get dismissed. They can't legally detain you at the border for a DOMESTIC investigation, which is what they were doing, so they had to frame it as a border security detention to lock him in that room and have domestic LEA start questioning him. It shouldn't be difficult to prove this was abuse of border authority, and that'll get the "destruction of evidence" charge tossed. (it's like you can't be arrested for resisting arrest)
- this whole thing happened because they wanted to coerce him into letting them search his phone but couldn't get a judge to sign off on a warrant for that, so they got the bright idea to have customs trump up a "random search" to lock him in a room with LEA (INSTEAD of customs) to do their illegal detention/investigation. They're basically using customs to bypass the courts on getting a search/arrest warrant. I'd wager there's an excellent chance this alone will get the case dismissed. The smart move for them would have been to have carefully "coached" the customs people on what to do and let them handle it. That might fly in court, but not this. Customs wasn't performing the interview and search, LEA was, and that *should* make the whole detention unlawful, which will vacate the Destruction of Evidence charge.
So he has a variety of defenses here, and he doesn't have to pick just one. He can raise them all, and if any of them are upheld, he walks. This is why he's VERY likely to win this case. None of his defenses are air-tight, but they're all pretty good, and he can try them all. It's basic statistics - if he's got five defenses and they each have a 30% chance to fail, that still cuts him free more than 99% of the time. And I think his odds are much better than 30% on these defenses. It's going to be a hassle, could take quite a long time, and theres's going to be legal bills to pay, but I expect the charges to be dropped or he will prevail in court. (we may even see the EFF get on board)