Massachusetts Supreme Judicial Court is tackling an important issue. A little background: Generally government law enforcement can't compel a password or decryption unless it's a foregone conclusion that they're going to find what they're looking for. The problem that the court is facing is what is the burden of proof needed in order to consider a result a "foregone conclusion"? Generally, they're not allowed fishing expeditions in other people's laptops and phone, due to the 5th Amendment against self-incrimination. I've been told by experts that there is a legal difference between searching a device and searching a house that causes the former to violate the 5th Amendment. I must admit that I didn't understand the answer.
If you want to wade through the legalese, there are a few briefs linked here. If not, at least know that this issue is being addressed and that general 5th Amendment doctrine takes the stance that the government must prove that they are not violating the law. The defendant does not have any burden of proof and is automatically considered correct absent a compelling argument otherwise. To put it another way, "Tie goes to the defender."